If layer wrapping is turned on (for x or y or both) for a layer, background obstacle information becomes wrong.
As seen in this file: wrapping_bug.mfa
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If layer wrapping is turned on (for x or y or both) for a layer, background obstacle information becomes wrong.
As seen in this file: wrapping_bug.mfa
It's by design. For the first layer, when the Wrap options are selected AND the "Handle background collisions even out of window" option is selected too, then the collisions between active objects and the background work like in the other layers, i.e. they are tested for each backdrop object and not with the global collision mask. That means that there can't be "holes".
In your example, the second quick backdrop object is a hole in the collision mask. This works well in the first frame as the Wrap options are not selected, so the collisions are tested with the global collision mask, which contains "no collision" bits in this rectangle.
In the second frame, as the collisions are tested for each backdrop object, the active object always collides with the first quick backdrop object.
This limitation can't be changed. Originally, in the first beta versions, the Wrap options were disabled for the first layer, but as testers asked for them to be enabled if possible, I've enabled them, but I had to add this limitation so that they work.
Yves.