Well, I have some new info about this. It is still doing that in live version of my island (which I finished and uploaded 8 hours ago), but in my newly created private versions it is not happening anymore while I am doing a Playtest with another account, which is for the first time since I created the system for leveling up with Stat Creator in this island soon after Update v33.00 went live.
But only changes that I did in last few hours is that I changed 1 screenshot in the map (which should have no effect on this), renamed few devices in connection with Stat Creator so they don’t have “XP” in their names anymore (which also should have no effect on this) and then I changed few settings on these devices, but after some testing I changed them back to the values that they had before. So I don’t understand why it is now OK in all new Private versions that I am doing right now.