this is a mistake i commonly see
lets say theres a scene where the attacker kicks the victim mid-air
once the action happens the animator seems to be busy animating the victim falling, while leaving the attacker flying in mid air, when they are animating the fall they remember the attacker then leave the victim STILL in mid-air while the animator is busy with the attacker

solution: remember that you have multiple figures you put in the air and gravity exists