It is probably a technical problem on the part of Facebook, i.e. a false recognition. It is also possible that someone claims rights for himself that he actually does not have. You can make a dispute here:
We tested the dispute functions on facebook and unfortunately never received an answer. So these forms are useless.
During our research we even read about other musicians who get copyright claims on music they just produced themselves and uploaded as video on Facebook. Facebook's music recognition is so bad that certain similarities are enough.
Facebook is slowly dying anyway and this is one more reason to go for more advanced platforms. Not everything goes smoothly on Youtube either, but at least you have the possibility to dispute and above all you can see who the copyright claim is from.