Well, am not 100% sure, but. I think that a newly created instance actualy gets created in the next tick.
You can apply actions to a newly created instance, right after a "Create" action, but you can't do picking of that instance before the next event.
But the 'on start of layout' does not execute in the next tick. This makes the pick events beeing skipped.
There is a simple trick to know if your 'on start of layout' has a problem with picking. And that happens a lot if you are not carefull. Change the 'on start of layout' to 'on mouse clicked'. If it works now, you need to bring the events out of the 'on start of layout'.