I actually have the opposite issue: I've created several tab groups during Monterey beta and now those tab groups and the tabs within them are stuck in that initial version and I cannot update them anymore. I close a tab and quit Safari, next time I open it it's back where it was. I move tabs into the default tab group (did this with all tab groups), next time I start Safari the tab groups are back there, closed tabs reappear, newly opened tabs disappear. I cannot get Safari to save the tab and tab group setup no matter what - tried deleting cookies, history, local storage...