Why does the left rear sliding door open and then close. Does not stay open.

This is an automatic door? the little electronic signals to/from the door are getting all confused- kinda like the confused electronic signals in my brain as I get older- must be a sensor out- the one that tells the brain "hey I'm open now and want to stay open!"

I had the opposite issue where I was doing some work out of the side door of my 2012 Caravan and when I finished, I pushed the button to electrically close the door and it would get almost all the way shut then rebound to open fully again. WTH? Push again - close - close - close - OPEN! Close door manually, same deal. Grrr....Pull hair....So I looked all around, is something jamming it? Nothing in the track, nothing in the jamb, wait there it is - part of the work I was doing involved small magnets and one had apparently slipped out of my hand and snapped itself to the upright part of the door pilar near the latch where it kinda blended in with the other metal hardware. I guess it was just thick enough to keep the door from latching which tripped the emergency anti-pinch sensor, causing the door to rebound exactly as it was designed to. Modern living!