double chests separate for item frames when returning from nether

soon as I exit the nether the double chests' look like a single chest with a 1 block air gap then the item frames float in front of the chests'. From the little I know, it looks like it's happening from chunks that were previously unloaded. If a log from anything is required, could someone post a link for the how-to.
I searched a couple times to check for duplicates. I didn't see anything new, although I could be doing it wrong.