The un-patched release may either have some ui lag or playback will be stuttering if the default NotSoDirect output plug-in is being used. The post-release updates for the build fix this problem
The video window if set to auto-close on playback stopping doesn't appear to follow that setting in all instances. Cause is still to be determined
The media library window may appear to show & then close during initial loading if the portable plug-ins are enabled & specifically pmp_njb (for Creative devices) is enabled with it causing the problem along with making loading much slower). If you don't need this device support then it's best to disable that plug-in via Preferences -> Plug-ins -> Media Library -> Portables
The shuffle table may not act as expected & is still to be finished being re-worked. This was also present in the 216xx builds & possibly 215xx.
SNSF sets won't play correctly or at all which is still to be investigated fully.
Smart App Control with Windows 11 can either cause the first run after an install to take an age or it'll just randomly block dlls from being loaded (e.g. image.w5s) which depending on what's blocked will either prevent WACUP from being able to complete loading or it'll be somewhat hobbled often until restarting & then everything will usually be allowed to load. I don't like this!