As of the last few beta builds playhead rendering while using the multicam view seems to be quite juttery at best and completely stops moving at worst (playing back at 2x speed is pretty bad for it right now and can even result in the user getting stuck and unable to stop playback for a while as premiere stops responding to inputs).
What's weird is that manually moving the timeline while playback is occurring seemingly causes the playhead to update its position like normal. I've attached a video showcasing this behaviour.
My timeline at current if 3x 4k clips in a multicam nest (all proxied at prores_proxy at 50% render scale), and 4x lavs. My timeline at current is near 5h in length with about 2.5h of rough cut edits. Moving to a smaller timeline makes this behaviour slightly better, but still incredibly noticeable.
Video playback itself is also perfectly fine with no dropped frames, and dropping the playback to 1/16 also has no effect on this issue occurring.
Another interesting thing is it appears is the 3rd video I've attached; you can see during playback the timecode on the timeline panel itself is super juttery, but the one of the effect controls window is perfect - UNTIL I start panning with the hand tool, then they literally swap haha
Windows 11, Prem v25.1.0 (build 12)
5900x, 4070ti super, 128gb 3600MT/s Ram, all media on ssd's
Media all 4k h264 8bit-420, prores proxy at 25% res scale