Yes, I updated the player.
I even had to completely reinstall it because after the update nothing worked anymore^^
I am SO glad you asked for a peace of code...
I tried to put something together, but was unable to reproduce the bug.
Then I made an output every 2 lines in my original code and narrowed the "bug" down to a file 2 layers deeper...
That was the issue:
SetTextDepth(btn._text, text_depth)
SetSpriteDepth(btn._text, btn.depth)
So no bug, just a very stupid me that sets the depth of a sprite with the id of a text...