Hi, very likely it was nothing to do with the teams upgrade. It appears the green screen and flicker issue with the OBS virtual cam into MS teams is very likely caused by having multiple monitors. Using OBS for 5+ years, with teams, zoom, etc with no issues. Suddenly with version 28 and then version 29 of OBS I encountered the green screen/flickering. I'm on a MacBook Pro 13" 2020 model(Intel) 32 Gig Ram, 2TB SSD and latest OS. After both upgrades, uninstalled OBS reinstalled, plus teams, zoom, etc etc - with no luck and spent days digging around to try and resolve.(Even purchased ManyCam with a view to start using that - sorry OBS....lol) In both instances I wiped the MacBook and reinstalled OS, plus all software....a lot of time spent - as am heavy user of OBS for work conferences etc etc.
None of the above worked.
What did(almost unbelievably) work after all the above did, disconnect all external monitors - I have 2 34" LG monitors - except the webcam and reboot machine. (For folks on desktops - leave just primary monitor plugged in - was not able to try this as am on laptop but assume this is something to do with multiple monitors not just the fact I had external monitors plugged into laptop)
1. Start OBS
2. Start MS Teams
Immediately the OBS virtual cam was working in MS Teams.
3. Shut down Teams
4. Shutdown MS Teams
5. Shutdown machine
6. plug in all external monitors
7. Boot machine
So far after multiple reboots thorough the course of the last 2 weeks - it is still working. The only issue is that very occasionally the video is jerky/stutters in MS Teams. I've tried without the external monitors plugged in - but this occasional flicker still happens - but - it is now usable. Also now working in zoom.
The green screen/flicker issue never appeared in the web version of MS Teams, and have now as a result of above been able to switch back to the desktop version which is more feature rich than the web version.
Hope this helps someone given the time and hassle I spent trying to resolve this. Please do post here if this solution works for you - we can perhaps then point to multiple people having same issue solved in same way and the technical folks can then perhaps figure out a proper fix for this.