Joining a meeting in a group chat doesn't work until I disable and re-enable audio or video

[Susurrus]

Steps to reproduce

1. Colleague calls me in a group chat I'm in
2. Have my webcam & mic on and join the call
3. I join the call, but my colleague doesn't react or see me.
4. I can see & hear him.

Outcome

What did you expect?

He should be able to see and hear me.

What happened instead?

He wasn't able to until I toggled my webcam off and on

Operating system

Fedora Linux

Application version

Element version: 1.12.26 Crypto version: Rust SDK 0.18.0 (16a138b), Vodozemac 0.10.0

How did you install the app?

https://app.element.io

Homeserver

mozilla.org

Will you send logs?

Yes

[Susurrus]

I submitted logs from after being on the call for maybe ~10m and had no audio/video issues after the initial hiccup.

I've seen this issue happen a few times and consistently on my end over the last month-ish so I decided to finally file a bug about it. I believe I've also seen it on 1:1 calls on Android, but haven't tested that in a while to confirm.

[Susurrus]

So it appears to be turning on the video triggers this. I just had this happen again in my current call, I joined and waited for several seconds and my microphone and video were on when I joined the group call so I could see my video fine, but my colleagues video was all black. I disabled the microphone and waited a second. No change. As soon as I unmuted myself, his video started showing and I could hear him and everything was working.

I'm on the mozilla.org server and he's on matrix.org in case that matters.

[TemoCrevlis]

These things have also been happening in my case but I didn't pin point what actions were causing it. Hopefully a fix of this issue is effective.

[Susurrus]

I did have a call yesterday or 2 days ago that did work within a couple seconds without me toggling anything. So this isn't a 100% persistent issue on my end.