In reference to the community Subscribe, Favorite, and Block actions accessible via the three dot icon to the right of the community name at the top of the screen, the Favorite/Unfavorite actions function normally on community feed pages, but don't switch to the opposite action when tapped as the other two actions do, or as Favorite itself does do when attempting the same from one of that community's post pages.

Note that the Favorite action can be manually updated on the community feed screen either by leaving the screen and returning to it, or adjusting the Block or Subscribe setting after adjusting the Favorite setting.