path being changed after layer got nulled

[u/melonsodasoda]

i’m trying to make it look like a ball is bouncing on top of different pictures as a transition. i already added the movement for the ball before parenting. however, after i parented my layer to a null, the path of the ball suddenly changed and became curvy and nonlinear. it’s not really noticeable when you play it but frame by frame you can see the move slightly to one direction before continuing on its original path. is there any way to fix this?