[Due for payment 2026-10-21] [$175] LHN sometimes doesn't show unread chats until the chat is opened

@mallenexpensify

Problem

Over the past few days or weeks, chats with new messages sometimes don't appear as unread in the LHN. The unread state shows only after the user opens the chat manually.

Details

Platform: Unconfirmed (possibly web)
Reproduction steps: Not known yet. The issue happens on and off.

Next steps

Find reliable steps to reproduce the issue.
Check whether the existing LHN logging captures these cases. If it does not, add telemetry to detect when a report has unread actions but the LHN doesn't show it as unread.

Reported in Slack.

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Upwork Job URL: https://www.upwork.com/jobs/~022107043087024337291
Upwork Job ID: 2107043087024337291
Last Price Increase: 2026-10-05

Issue Owner

Current Issue Owner: @mallenexpensify

Proposal

Confidence: medium. The code and the PR that introduced the change support this. I couldn't check production logs in this run, so it isn't confirmed for a specific user yet.

What is the root cause of that problem?

The LHN is fine. On web, the new-message update never reaches the client.

Since [No QA] fix: skip reconnectApp on pusher socket blips (merged 2026-08-29), web skips ReconnectApp when the Pusher user channel resubscribes, unless pusher-js reached the unavailable state (PusherUtils.ts:58-67, Pusher/index.ts:115-118).

A socket dies silently, for example after sleep, a Wi-Fi change, or a throttled tab. pusher-js only notices this after its activity and pong timeouts.
It then reconnects in under 10 seconds, so it never reaches unavailable. The resubscribe skips the sync.
Pusher doesn't replay events. Messages sent while the socket was dead are lost.
Gap detection only runs when the next server payload with previousUpdateID arrives (applyOnyxUpdatesReliably.ts:50-51). Opening the chat sends OpenReport, which triggers it. That's why the unread state appears only after the user opens the chat.

PR #99084 calls this out in its own test step 10: "Verify the message does not appear yet. This is the accepted tradeoff… an idle tab stays stale until one arrives."

What changes do you think we should make in order to solve the problem?

In src/libs/Pusher/index.ts, also mark an outage when the socket drops after an activity or pong timeout (a silent death). Optionally, also mark one when the time since the last inbound socket message is longer than a few seconds. Short blips still skip ReconnectApp, and silent deaths sync again.
Add a unit test to tests/unit/PusherSubscribeWebTest.ts. It should cover a pong-timeout drop followed by a fast reconnect, and check that ReconnectApp fires.
For the telemetry the issue asks for, add a Log.info when gap detection runs. It should include the gap size and the time since the last "Skipping reconnect" line. Then we can measure how often skipped syncs leave clients stale.

What alternative solutions did you explore? (Optional)

Revert [No QA] fix: skip reconnectApp on pusher socket blips #99084. This is simple but brings back about 54k extra ReconnectApp calls every 2 hours, per the PR.
An LHN rendering bug. I traced the code from isUnread to the LHN row and found no memo or cache that skips a changed report. Opening the chat repairs the data itself, which points to missing data, not a render bug.

Investigation details

Web only: native's claimOutageSync always returns true (index.native.ts:481-483).
Timing: [No QA] fix: skip reconnectApp on pusher socket blips #99084 shipped about 2026-08-31, which matches "past few days or weeks."
Related changes: [No QA] stop the pong watchdog from reconnecting Pusher (2026-08-19) removed the earlier safety net for [$250] False "offline" indicator after machine restart — stale Pusher websocket not re-established. Lower the Pusher activity and pong timeouts from the SDK defaults (2026-09-14) means silent deaths now reconnect fast and always take the skip path.
How the LHN decides a row is unread: isUnread compares lastReadTime with lastVisibleActionCreated on the report (ReportUtils.ts:10016-10046, SidebarUtils.ts:844). If the report update never arrives, the row stays read.
Less likely cause: the chat was auto-marked read by another mounted screen, tab, or device (useMarkAsRead.ts:199-241). This fits less well, because the unread state does appear after the chat is opened.
To confirm with logs: for an affected account, look for [PusherUtils] Skipping reconnect, socket recovered without going unavailable, then no Handled multipleEvents line for the missed message, then a gap-detected line when the user opens the chat.
Questions for reporters: When this happens, does the LHN preview text or row order also not update? Is there no notification? Are you using the Unread tab or All?

Possibly related issues:

Marking a chat as unread doesn't stick — client immediately re-reads it, and other clients never see the change (open). Its bug 2 is a client that never receives updates.
[$250] Messages not highlighted as unread in LHN on web / real-time message updates not reflected (closed, couldn't reproduce). Same symptom, before [No QA] fix: skip reconnectApp on pusher socket blips #99084.

Next Steps for Contributor+ team:
To accept: @MelvinBot implement [this](https://github.com/Expensify/App/issues/102973) to create a draft PR.
To refine: @MelvinBot <your feedback>
To reject: Explain why you are rejecting Melvin's proposal.

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@dmkt9

Triggered auto assignment to Contributor-plus team member for initial proposal review - @dmkt9 (External)

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@dmkt9

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Proposal

Please re-state the problem that we are trying to solve in this issue.

On Web, unread chat messages do not highlight as unread in the Left Hand Navigation (LHN) until the user clicks and opens the chat report.

What is the root cause of that problem?

In src/libs/PusherUtils.ts (lines 60–67), when Pusher re-subscribes to the private user channel, it calls Pusher.claimOutageSync():

unregisterPrivateUserChannelResubscribe = Pusher.onChannelResubscribe(getUserChannelName(accountID), () => {
    if (!Pusher.claimOutageSync()) {
        Log.info('[PusherUtils] Skipping reconnect, socket recovered without going unavailable');
        return;
    }
    Log.info('[PusherUtils] Pusher re-subscribed to private user channel, triggering reconnect');
    reconnect();
});

In src/libs/Pusher/index.ts (line 116), hasUnclaimedOutage is only set if the socket reaches the unavailable state:

hasUnclaimedOutage ||= states.current === 'unavailable';

When a socket connection drops silently (e.g. laptop sleep, Wi-Fi network switch, browser throttling idle tabs, or activity/pong timeout) and reconnects in under 10 seconds, pusher-js never transitions into unavailable.

Consequently:

claimOutageSync() returns false, skipping reconnect() (ReconnectApp).
Pusher does not replay missed real-time events that occurred while the socket was disconnected.
The report's Onyx state is never updated with the new message until the user navigates into the chat, which triggers OpenReport and fetches the latest report data.

What changes do you think we should make in order to solve the problem?

In src/libs/Pusher/index.ts:
- Track when a socket disconnect occurs due to transport error or connection timeout (such as activity/pong watchdog drop) by setting hasUnclaimedOutage = true.
- Ensure that any resubscription that occurs after an unnoticed connection break properly triggers ReconnectApp via claimOutageSync(), while keeping immediate blips without missed events optimized.
In src/libs/actions/applyOnyxUpdatesReliably.ts:
- Add telemetry logging in gap detection to monitor gap size and delta time since the last skipped reconnect to ensure zero dropped syncs.
Unit test:
- Add a test case in tests/unit/PusherSubscribeWebTest.ts asserting that an activity/pong timeout drop followed by a fast reconnect correctly marks an outage and triggers ReconnectApp.

What alternative solutions did you explore? (Optional)

Reverting PR [No QA] fix: skip reconnectApp on pusher socket blips #99084: This would trigger excessive ReconnectApp calls on transient socket blips (~54k extra calls). Targeting actual timeout/drop disconnects rather than relying solely on unavailable preserves efficiency while eliminating stale state.
Client-side polling in LHN: Unnecessary and contradicts Onyx push-driven architecture.

Contributor details
Your Expensify account email: camesenin@gmail.com
Upwork Profile Link: https://www.upwork.com/freelancers/~0170d6b02e9440e604

UPD: I see the log added by us was triggered several times, but I can't verify it over real FS sessions today (data capture will be resumed by FS tomorrow).

@mountiny

I've rechecked logs vs sessions and for spotted two cases

FS link 1 time 11:18: report is shown in LHN for a moment and then disappears from LHN (though the user currently has it open).
It looks like for some reason check for current report didn't work. I wasn't able to reproduce it so I'll keep an eye on similar cases if any.
FS link 2 time 8:28: expense report with unread replies from May isn't shown in LHN.

I've reproduced the same an it looks like it's the thing for the one transaction threads that we intentionally skip it from display in LHN, even if it has some unread (check 1 and check 2):

lhn_transaction_thread.mp4

See, at first the thread is bolded in All tab, and not visible in Unreads.
After Clear cache & restart it's not visible at all. Only when user opens is they see the unread message.
Just to confirm, is it expected behaviour @mountiny?

@mallenexpensify

Triggered auto assignment to @mallenexpensify (Awaiting Payment)

@VickyStash

Payment Summary

Resolving PRs:

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BugZero Checklist (@mallenexpensify)

I have confirmed assignees, roles, and Upwork contracts look correct
I have paid out Upwork contracts / manual NewDot requests
[BugZero Assignee] I have created a GH issue for creating/updating the regression test once above steps have been agreed upon

@dmkt9

Payment Summary

Contributor+: @dmkt9 due $175 via NewDot

@mallenexpensify

Contributor+: @dmkt9 due $175 via NewDot

@mallenexpensify I'm still receiving payments through Upwork. I've reviewed two separate PRs: #103147 and #103463.

@dmkt9

@dmkt9 can you please accept the job below? Please reply here and tag me once you have.
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@mallenexpensify

46. @dmkt9 can you please accept the job below? Please reply here and tag me once you have.

@mallenexpensify I've requested $350 for reviewing two PRs

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[Due for payment 2026-10-21] [$175] LHN sometimes doesn't show unread chats until the chat is opened #102973

Problem

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Proposal

What is the root cause of that problem?

What changes do you think we should make in order to solve the problem?

What alternative solutions did you explore? (Optional)

Please re-state the problem that we are trying to solve in this issue.

What is the root cause of that problem?

What changes do you think we should make in order to solve the problem?

What alternative solutions did you explore? (Optional)

29 remaining items

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BugZero Checklist (@mallenexpensify)

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[Due for payment 2026-10-21] [$175] LHN sometimes doesn't show unread chats until the chat is opened #102973

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MelvinBot commented on Oct 5, 2026

Proposal

What is the root cause of that problem?

What changes do you think we should make in order to solve the problem?

What alternative solutions did you explore? (Optional)

melvin-bot commented on Oct 5, 2026

melvin-bot commented on Oct 5, 2026

melvin-bot commented on Oct 5, 2026

camesenin commented on Oct 5, 2026

Please re-state the problem that we are trying to solve in this issue.

What is the root cause of that problem?

What changes do you think we should make in order to solve the problem?

What alternative solutions did you explore? (Optional)

29 remaining items

VickyStash commented on Oct 15, 2026

VickyStash commented on Oct 16, 2026

melvin-bot commented on Oct 20, 2026

melvin-bot commented on Oct 20, 2026

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BugZero Checklist (@mallenexpensify)

mallenexpensify commented on Oct 21, 2026

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dmkt9 commented on Oct 22, 2026

mallenexpensify commented on Oct 22, 2026

dmkt9 commented on Oct 23, 2026

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