MultiBeast, UniBeast, Chimera, etc. showing generic package icon instead of their custom icons
I found out what was causing this...I had an application called Keka (it handles .zip, .7z, .rar, .tgz, and just about any other archive file imaginable) installed, and it was my default application for opening all archive file types. I removed Keka and switched back to The Unarchiver, and now the applications are showing their correct icons again.