> Can you post your capx, or a screenshot of the event sheet?
Hopefully that should work for you (To download)
I remade this and having trouble getting your way to work at all now
This works (edit deleted original Pick all event, wasn't needed) , just double checked, and they start at very nearly all the same time, and find path.
System | Compare Two Values | ai.PickedCount = ai.Count
side note on your capx, you are better off using 3 individual sprites for the obstacles, as this will be much more efficient than a large image with lots of collision points.