Well everthing is in the title, took me 3 days to figure out why i was having some issue with my AI backgrounds detection only on iOS, was thinking of a bug with MoveSafely2 or a bug in my events but no, the bug was so simple..
If you check "collision with box" for a background object, on iOS the box will miss a part on its left!
Check the screenshot:
Here's a MFA to test:
You can jump trough the background like on the screenshot, and you can also fall from the top if you move slowly.
The square background doesn't have "collision with box" checked so there is no issue with it.