I have constructed a couple of buildings that have multiple floors with each floor having doors. Doors and door placement used to work until now, doors that were originally placed explode and go into your inventory now and it will not let you place a new door unless you are on the ground floor, other items will place on the upper floors just fine.

Both buildings have a mix of regular size cobblestone, wood blocks, and wood slabs as outside decks
I have also downloaded my realm world on to my computer and the bug does not exist and everything works. However when I reset my map and uploaded my copy back on to the server the bug returns. So I believe this is a server bug. I hope this helps.