Move the Box

In level 18, putting the central box on the middle tile with the left and right box on their respective tiles fails to complete the level.

In Level 18, it's possible to get the boxes into place without triggering the level completion. Putting the boxes onto different target squares makes it work though.

When I completed what I assume was the final puzzle, a text message briefly appeared but disappeared before I could read it. After that I was able to reset the puzzle, but the player remained where he was when I solved it (I took a picture).