Refrigerator Vent?
 

Hadn’t noticed this before, but when fully up, there is a gap behind the refrigerator cabinet.

Is this supposed to be sealed off?

I would say yes. I wouldn't use it on propane till it is repaired. Electric use would be ok but you will have increased heat dumping into the coach because it isn't venting to the outside. Be safe!

That’s what I thought.

Anyone able to take a pic of theirs for reference?

Are you sure your top is ALL the way up. If the seals are up against each other, that gap won't be there. Cables stretch and may just need adjustment. Very common.
If they are properly adjusted, then I'd guess something is missing.
Good point about NOT using propane.
Tree

No, not using propane and the top is up all the way - seals are tight.

A picture would be helpful.

Thanks

Can't do a pic as I'm away from home, but I stuck my hand down there behind the refer. Mine is the same as yours except I have thick carpet-like material that goes down further than yours and THAT is the seal. Must say, I've never noticed that before. The rubber bulb seal is 6 or more inches below that on the outside. I guess the two carpet-like products makes enough seal.