MSFS communication issues

I switched to MSFS a few months ago and have pretty much only flown Fenix A320.
I have experienced an annoying issues which frustrates me.

The problem is that my VHF or COM automatically changes frequency without my knowledge or action which is a problem flying in controlled airspace.
What makes it even stranger is the frequency isn´t even a valid one.

I think I have switched off all ATC prosibilities in MSFS.

Has anyone else experienced this and is there a solution to this problem ?.