Here is a link to a screen recording where you will see me trying to delete an anchor point on a shape but it deletes the anchor of the shape behind it. I then move the shape (change its colour to show that its in front) and I am able to remove the anchor. However, if I move the shape back over the bottom shape and try to delete another anchor point, it once again deletes the anchor of the shape below. The same happens when I try to add an anchor.
I can't for the life of me figure out why this is happening.
There was a post about this a few years back with no solution.