Well, this bug is pretty much, that whenever you try and place a painting on a sign, the painting will be "placed", as in your item will be lost, until the sign in broken. And say you have multiple paintings, and you try to place it on this one particular sign. All paintings will be lost until the sign is broken. And once broken, a lash of paintings will spill out of thin air. Painting used to be able to be placed behind signs.

Notice in Picture 1, that I have 63 paintings. Then in Picture 2, I have none, due to the loss placed onto the sign. Then in Picture 3-5 shows me breaking the sign, and the paintings "spilling".