You have a mix of face palm error, object/project settings error and some arithmetical errors
The face palm error is the fact that the GridTiles layer isn't transparent.
So you don't see what is created on Layer 0.
The object settings error is that you don't have the same Cell Size value in your finder in your ObjectDump and in your Gameplay Layouts. It does not necessarily cause the bug, but well... better safe than sorry (:
The project setting error is that you have a layout width which is not a multiple of 64, so it doesn't look good
The arithmetical ones are where you position your end point, and is a bit bound to the layout width error and some wrong calculation
You try to place the end sprite at floor(WIDTH/cellSize)*cellSize which in fact put it out of the layout. The proper formula would be (floor(WIDTH/cellSize)-1)*cellSize
Also since the origin is at the center of the sprite, you have to offset it to half cellSize.
So the proper formula would be:
X = (floor(WIDTH/cellSize) - 0.5) * cellSize
Y = (floor(WIDTH/cellSize) - 0.5) * cellSize
Oh and also I think you were generating the maze constantly... soooo