Joining a DM shows infinite room join events in the timeline until app crashes

Steps to reproduce

I don’t know how to trigger this bug, but it was reproducible until I opened the app

1. Other person sends some messages in the DM
2. Receive an invite to a DM and click the notification
3. See the invite dialog open in the app (it doesn’t say who the invite is from, the title of the dialog is !room1d:homeserver.org
4. Click “Join”
5. App crashes

I could reproduce the behaviour until I opened the DM in the web app, then it started working correctly. I tried submitting a rageshake after the app restarted and it claimed to have submitted correctly but I can’t see it in the rageshake repo.

Outcome

What did you expect?

See DM

What happened instead?

Room opens, see a “membership change” event in the timeline, see number of the membership change events counting up. App crashes.

https://user-images.githubusercontent.com/51663/173808555-bcc7d803-75a9-4028-b7ff-600ede9f6900.mp4

Your phone model

Pixel 2

Operating system version

Android 11

Application version and app store

Element version 1.4.20; Matrix SDK 1.4.20, olm version 3.2.11

Homeserver

matrix.org, the other person is on element.io

Will you send logs?

Yes

Are you willing to provide a PR?

No

[richvdh]

I believe this was introduced by https://github.com/matrix-org/synapse/pull/12903

[weeman1337]

Also happening if both are non-Matrix.org (Synapse 1.60)