Pad disconfigures in the middle of a song

This started to happen in 5.3 Alpha 4.5, didn’t happen with previous versions.

My pad gets disconfigured seemingly at random, sometimes in the middle of a song. Suddenly it stops recognizing my input, I lose and I have to remap the keys. Looking closely, it seems that the software thinks that my pad is now “Joy 2”, and then “Joy 3” and so on. I’ve reached even “Joy 6”. Sometimes it works Ok, but lately it hasn’t.

I attach two screenshots of before and after I remap the pad. Tell me if you need more info.