Well, it's not really a false positive in that it's even reported as malicious
in any sense of the word.
It's simply exactly what MBAM calls it to begin with: a potentially unwanted modification. One that MBAM is telling you is in itself completely harmless but might not
be what you want it to be.
Since you've determined that it is in fact NOT an unwanted modification, feel free to simply add this item to your exclude list on the next scan and be done with it.
(Personally I have two or three of these PUMs too but I've done every one of them myself on purpose. I just had to gently tell MBAM about it.)