I have an Apple TV 4K gen 2 with 15 MBps remote connection to the server that doesn't work watching in progress recordings. I'm pretty sure its related to ios15. Basically it will hang after watching for less than 5 minutes, it will show a static image. A quick check on the server shows that its still sending data but the apple TV is still showing a static image with no sound. It's not locked up because I can back out and try again but still its unusable. It will also hang every time the server changes adaptive transcoding on anything I watch. It definitely used to work great. I'm hoping ios15.1 fixes it.
I just switched back to my Firestick 4K which works fine in the exact same situation. My iphone and ipad also work great remote as well and they are ios15. I have an apple TV 4k 1st generation that is local to the server that isn't updated yet and it still works great.
Like I said earlier, I'm pretty sure Apple broke it so I'm hoping they fix it. I have an email chain with support but I decided to start a thread to better keep track of the issue. It looks like there are two other threads that may be related.
While watching live TV will freeze up and say connnection lost - Channels Apple TV / Troubleshooting - Channels Community (getchannels.com)
Lots of Stuttering and Buffering in DVR Playback on ATV4K - Channels Apple TV - Channels Community (getchannels.com)
Let me know if there is anything I can try to troubleshoot the problem. Should I install the beta channels app?