the collision points of the animation ID FALL at the bottom weren't exactly at 26, I set them exactly and the stutter is gone, I still recommand to use a dummy rectangle object for the collisions and to pin the player animations on it to prevent those kind of issues, still searching for the stutter on the edge
EDIT: I think it, once again, has to do with collisions, ID FALL is a little larger to the left, so when the player is not on the floor, it trigger the falling animation, but then the hitbox is larger, so it triggers back on the floor, and so on, again, this kind of issues could be avoided using a rectangular, invisible, fixed size object that has the behavior platform and pinning the player sprite animations on it.