While trying to edit the points of a line with selection tool, those points move sporadically

as soon as I go into the object and move it there at all then the problem resolves itself for that keyframe only and happens again once you make a new keyframe. that's why the right leg was unaffected, I had moved it in that keyframe. I want to know if there's a more permanent solution so I don't have to go into the object every keyframe?