If the song is corrupted in the BBMO, you might not be able to move it in your Play List.
I tried opening my project with a corrupt song file in the BBM (hoping to have been able to move it) but the BBM treated it as corrupt. I was able to delete it from the BBM though.
Thank you for reaching out! I’ve sent this to the dev team. They are currently overwhelmed with requests, but they will take a look at it. If you encounter any issues, please email support@singularsound.com directly.
How about wishing for an early Christmas gift from the dev team, BBMO 1.5.1+ with these and other bugs fixed? Could it happen? Fingers crossed in hope.