maps cannot be placed on adjacent walls

before a recent snapshot, if 2 blocks were placed diagonal to each other (as pictured) and item frames were placed on the interior sides (as pictured on the left side of the bunny) then maps were added to the item frames, the 2 maps will stay put

after the update, however, one of the two item frames will fall off

(as pictured on the right side of the bunny)

this makes some map-based designs unnecessarily impossible

please fix this

-zoey