This is something that appears to be normal for the new update in Minecraft, it's weird but the chests next to each other like that are still double chests, I guess someone thought it was cool to make the double chests look like this. Idk tbh.
It's probably because you're playing on a 1.13 client. The server is still on 1.12.2 Just go back to 1.12.2 and that shouldn't happen. For the record I play on a 1.12.2 client and do not have this issue.
