When using a clone command with the move option to teleport a structure downward non-solid blocks (chests, hoppers, and signs) replace each other (only visually).

The pictures show a structure teleporting downward one block at a time. The chest at the bottom begins to render in front of the objects above it although it is not really there (as shown by me standing in the "chest").
However, as shown in the last picture, when I relog everything is fine until I try and clone the structure again.
I should also mention that each time it teleports downward i get the debug error "Unable to locate sign at x y z".

I've tried everything I know to fix it and have been unsuccessful leading me to the conclusion that it must be a bug.