Room ordering has broken in RoomList, with ancient inactive rooms resurfacing as unread

[ara4n]

Steps to reproduce

Using today's nightly, with Rooms and People list ordered by activity with 'show rooms with unread messages first' enabled, after about ~30 minutes of use, random ancient rooms appear at the top of the unread messages section of the room sublists, seemingly replacing the correct rooms with unread messages which should be there.

Outcome

Rooms with unread messages are shown in the unread section of the roomlist, ordered by recency - rather than ancient idle rooms appearing there.

Operating system

macOS 12.0.1 on M1

Application version

nightly

How did you install the app?

nightly

Homeserver

matrix.org

Will you send logs?

Yes

[ara4n]

(rageshake contains more details)

[novocaine]

@ara4n experienced the behaviour on app.element.io - an old room bubbled up there, not e2e

[ara4n]

I've chased this down further - it looks to be a regression in element-hq/element-meta#862. The rooms which bubble up are being ordered based on the most recent profile change. However, it looks like it may be intermittent - I saw !XjXlEydwpKIBnirswa:gnugen.ch bubble up from the depths on app.element.io, but not on Nightly. I've also repro'd the bug on Amandine's Nightly (the same old rooms were being resurrected from the depths by Neil changing his nick on Nov 9th), so I think this is probably biting everyone.

[novocaine]

the same old rooms were being resurrected from the depths by Neil changing his nick on Nov 9th

that sounds like #15860 ..?

[ara4n]

...which was a dup of element-hq/element-meta#862 that nobody spotted. It should have been fixed by matrix-org/matrix-react-sdk#6595, if it hadn't regressed.

[novocaine]

or matrix-org/synapse#9716

[ara4n]

I just got bitten by this again.

[daniellekirkwood]

@kerryarchibald as we're looking at room list ordering, could you take a look at this and see if it's something straight-forward while we're in that space?

[ara4n]

This is still happening, with profile changes causing hundreds of rooms to be marked as unread and rise to the top - drowning out everything else.