P: Folder Favorite Setting Cannot Be Changed

After installing the latest release of Lightroom Classic 7.4 I'm unable to unmark my favorite folders.  In other words, folders that were marked as favorites before the latest release can no longer be unmarked.  I can, however, select a folder that was not a favorite before release 7.4 and mark it and also unmark it as a favorite.  I use this feature a fair amount so I'm pretty sure this issue started after the latest release but I cannot be sure.  Thoughts?  Seems like one of those pesky software bugs to me. I'm an experienced user so I do not think this is some type of user error.  The catalog is my master catalog and has about 600,000 images.  I did not have any favorites marked in my sub catalogs before the release.  They work fine but, again, the problem seems limited to the folders that were marked as favorites before the release.

[Update: All of the reports here except one can be explained by the confusing design of LR's "favorite groups".  See Robert Somrak's post and John Ellis' post. Thus, this topic is marked as an Idea, rather than Not A Problem, to capture the concept that the UI design is very confusing.

Patrick Philippot identified a bug where right-clicking an unselected folder creates two folder groups. It has been forked into this bug report.

There's another topic expressing similar confusion. I'm not going to merge the two, since that will hide all the useful replies.

- John Ellis, 3/10/20]