Hi, there's a bug in macOS 27 beta (carried over from 26) that causes base (non-Pro/Max/Ultra) M-series Macs to render certain UI animations, like Finder Quick Look and system dialog pop-ups (Restart, Shut Down, etc.), at ~30 fps unless screen recording is active.
Screen recording immediately restores 60 fps across the board. The Quick Look animation is also unaffected by the bug when viewing a video file.
I've reproduced the bug on multiple base M4, M5 and A18 Pro Macs in Apple Stores. Not reproducible on Pro/Max/Ultra variants.
I filed a bug report in April against macOS 26 and a few weeks ago against 27. I'd very much appreciate if any of you could do so as well if it affects your machines.
How to reproduce:
- Open Finder on any base (non-Pro/Max/Ultra) M-series Mac
- Press Space on any non-video file
- Observe ~30 fps animation
- Start any screen recording
- Repeat steps 1 and 2
- Observe fluid animation
Thank you in advance for your help.