Item frame duplicating map

I searched this out but couldn't find anything similar. If there's all ready a report please link this to it!

I am playing on a Realm.
I can get unlimited duplicates of maps by using the item frames.
Here's the details:
I am online alone usually (due to Blaze Death crash and no one being able to play) and I believe I was online alone all three times I got map duplicates. I got them twice by accident and then the third time I logged in I decided to try to replicate it on purpose.

I placed some maps in order in item frames on the wall (at first 5, then 6, then I duplicated the bug with just two maps). All you have to do is be all like "Geez, this wall is too small and now I have to move all these maps and frames and do the puzzle AGAIN." and start knocking maps out of their frames....every once in awhile a frame may get knocked off, but maps go flying and suddenly one of the maps will double and when it pops off the wall you get two copies of it instead of one. I couldn't do this with just one map, but with only two of them on the wall I got the second map off the wall to duplicate the second time I tried. It's some fast mouse clicking that seems to cause it.

While I was happy to have copies of maps without using up more resources I realize this isn't meant to work this way. lol