2D sprite renders a small part of another one with "Sprite Mode : Multiple"

Hello,

I'm stuck with a big issue in my game : As you can see there is a small black line on the top of the sprite (a brown square here represents 1 pixel in the game).

Actually this black line is a part an other sprite sliced in the same spritesheet (on the top of it) :

I'm stuck because i'm already using the Filter Mode to Point with a Maximum Size greater than the spritesheet size.

My sprites are all stick together without any blank space, so i'm asking if there is any solution to avoid Unity to take a small pixel of other sprites, or if I have to reimport all my spritesheets with a blank separation between each sprites (i got a lot so i hope i don't have to...).