Heartrate zones are randomly changed

I have a problem with setting the heart rate zones in my EPIX GEN2. I've set my zones manually to custom BPM, but randomly my watch (or Garmin Connect) sets them back to %LDHS or %Max HS. Sometimes also the sport specific zones are changed, or even sport profiles (within the user settings) are added or deleted.

This is really annoying, I now have to check before starting any activity if my zones are set correctly, and set them back to the correct setting.

Please fix this, its not something you expect from such a expensive watch.