Thanks for the fact you took the time to compare both tracks. What you write is exact what I thought myself too first. But later (when I checked the claim again to reply to it) I saw the claim is about the last part of the movie where people could play along with a karaoke track. That is just the BiaB track without my melody.

I contacted the original composer of the song the claim is about. He agrees that this is strange. He is going to communicate with the copyright company too... let's hope it works out right.