Question:
Are you feeding the panels on the lowest point or the highest point?
It's probably best to feed at the lowest so any air pockets can get pushed out.
I would still take one endcap on each of the suspect panels off and see if you can push a stick/rod through to the other end cap - who knows, maybe the labels are applied wrong - unscrewing the caps is not much work so it may be worth a try.
Another thing is that trapped air may then escape and alleviate this issue in the future.