First, I want to thank you Andre. It's rare to get such rapid responses from highly knowledgeable people.
I'm afraid re-tagging my entire collection is not a viable solution to this problem for me as it would take a very long time to go through and re-backup and then re-upload to various phones the affected portions of my library (re-uploading is particularly annoying as our phones don't have enough storage space to hold all of our music so I have to pick and choose what I upload to them). One of the primary reasons I chose Poweramp years ago was because it supported multiple genre tags the way my library was setup. As I see it, this could be considered a regression issue as it worked perfectly well for me for years. Is there documentation I can read on how to officially request a feature or a bug fix for this?