Accessing Microsoft Teams using organizational or personal credentials
That's exactly what we do, and as you write, it's worked for years.
Yesterday I was on the phone with Microsoft for hours and we discussed it, they say it's not in support.
So I completely reset a PC to factory settings, logged in the skype user and then logged in my meeting room user in Teams Room, and I can reproduce the same problem. (so much for the topic, it's because we don't use the skype account...).
They are currently analyzing my logs again. I am curious when we will get a solution...
One important note:
We do not use the default "Skype" user and have instead domain user accounts with autologin and Teams Room system in autostart.
This has worked the previouse 4-5 years until now.
I already started the Windows 10 IOT re-image process via USB-stick on one of the devices.
This time the device will work with default settings ("Skype" account) and outside of our domain.
I will update here if it works.