3x4 Painting needs a 4x5 space and 4x4 painting needs a 5x5 space

If I place a 3x4 or 4x4 painting and place anything one block up or to the left of the painting, it falls off. If I remove blocks behind the painting in this area, it falls off. A 3x4 or 4x4 painting won't show up unless this area is open.

Steps to Recreate:
1. Get a big wall
2. Place a 3x4 or 4x4 painting on it
3. Place a block to the left or above it, or remove the wall to the left or above it
4. Painting falls off