The issue could also be that the push rod on that side isn't adjusted properly.
There is a nut that you can loosen to adjust the push rod that is connected to the clamshell so the clamshell will close tighter. Without seeing it in person it is hard to tell, but it is something to check. You said it's a porsche shop, so they should of checked this already...
This is the nut/push rod I am referring to
