About color-coded-tilemap

Please help someone.
I used color-coded-tilemap extention because I want to use an 8x8 wall.
However, if I make a floor from the top to the ninth row, a zone where projectiles will not fly will be created.
Is this a bug because the code is simple?
As a result of various tests, it seems that the X of the player sprite occurs between 76 and 84.
This only happens when the projectiles use “sprites with a size of 16x16 and space at the bottom”.
For example, there is a problem with marbles, but not with apples. (However, the Y coordinate of the apple decreases by 1px)
I wonder why?
There seems to be a way around the problem, but I would like you to tell me if there is a way to solve it.
Thank you.