The error seems to appear almost at random sometimes. I can semi-consistently cause it to occur when my player character dies, but even then it won’t always. Sometimes it even occurs regardless if the player is dead/dying or not. I’ve seen conflicting reports online regarding what causes the error but I haven’t found anything concrete. It hasn’t caused the game to crash or anything yet but I’d rather not just let it slide.
I checked it out, and it seems that when two VisibleOnScreenEnabler2D objects enter the screen at the same time (when they send the screen_entered signal), this warning gets triggered. In your app, apparently two objects are appearing at once, which is causing the error to show up.
I’m not really sure about this, but it might be the case. Maybe using call_deferred could help you out.
I just double check all my scenes and not a single one sends the screen_entered signal. Strangly though I’ve also since been able to reproduce the error by walking atop or next to seemingly random scene tiles in my tile map, but it’s still too inconsistent to say affix the error to any one particular thing. So I’m stumped.