Placing a glass item frame in front of an inventory, placing something in it and clicking it again just rotates the item instead of letting you open the inventory behind.

Honestly, I almost feel this is intended behavior now that I think about it. I'll have to think some more but really it kinda is the type of thing where you would want it to be able to do that.

what you mean?

Im pretty sure regular item frames work the exact same

normal frames do that, yes, glass item frames shouldn't. It's a quark feature: