Anyone seeing issues with Teams fallback on the latest versions?

I was just emailing our rep about this. We are seeing really high memory utilization and server crashing. I suspected it was non optimized sessions and was trying to figure out fallback was working or not

I have a customer where when they got to the latest version, Optimized works, but Fallback is completely failing. Previous versions (before slimcore) didn't have the issue.

We have both Teams and Teams Classic in our deployed. Randomly new Teams will disappear from the start menu, the MSIX is missing from the users profile.