There are probably multiple causes to this problem, hard- and software.
It is the conjunction of them which makes it undebugable without lab equipment to separate causes.
Users on this thread made lots of tests.
I also made lots of tests with 4 different XA2 in parallel and noticed big differences with the same software.
I also noticed that hardware disassembly and contacts cleaning helped but didn’t solve the problem completely.
It is a headache + hair pullout problem 
It would be excellent if a good soul with lab equipment would try to join! 