It is a bug, but manual removal of one project works for me. I have not yet tested manually removing them all. The workaround is Settings > App Data Directory > Show followed by File > Exit and then delete file recent.ini.
I have a second thought about this now. The menu item says “Recent,” but the list you refer to is no longer “Recent Projects”. It is simply “Projects,” separate from Recent.
How about having the choice between Remove and Remove All when we right-click an item in Projects?
Or Remove Selected and Remove All (restart needed) ?
That would be nice, but that’s not a big issue if it stays as it is. Your workaround is good enough for me