Hi, I'm not sure I totally understand why we needed to connect to the pass through detector's body exited signal for, as you mentioned, if we delete a platform. Can you elaborate?
Also, is there a reason we need a passthrough detector aside from the reason you explain above?
The reason we use a dedicated area for pass-through is a little subtle, it's to reactivate the collision mask bit on the player after it stopped overlapping with the pass-through platform completely, when falling down through it. So next time you encounter a pass-through platform, you can stand on it again.
That's because those platforms are pass-through in only one direction, and by default, you can't fall down through them. So you need an area to know when you completely fell through them accurately.
Hope this helps, let me know if you have any more questions.