I can confirm this. Safari Version 15.0 (16612.1.29.41.4, 16612) It is an erratic behaviour because I was able to save 4 tab groups and those are still being saved when I make changes to them. However, any new tab group I create is gone after closing Safari. Additionally I have noticed that there is often a Safari window 'Untitled' that is visible from the Window menu but not accessible.

Same here, every time I wake the MacBook from hibernation the mouse scrolling is not working. Turning off and on the mouse fixes it. MacBook Pro M1, MacOs 12.0.1, MagicMouse 2