problem with tilemap collider and composite collider

Hi all! the problem is that the composite collider doesn't generate the shape well when the cell size of the tile map equals the size of the image.

In my case, the tile is a 64x64 image and if I set cell to 64x64 (in pixels) it will generate the following collider

And the problem is that the player will be stuck if z rotation is locked and will stumble if z rotation is not locked in this situation.

but if I set the cell size to 63x63, or more precisely, set x value less than 64 the composite collider can generate a nice rectangle.

the unity version is 2018.2.13f1 personal