Lift gate sensitivity

[Symetry]

I do Walmart order online for pickup . Been doing this pickup device since early summer , cuz I hate going in the store.
Ok.
Why does every time they load the cargo area , they push manual button to close the lift gate , it starts down , then stops , they try again , it goes back up to top , push again , same thing. I try the on inside , same thing.
But,
When I get out , go back, and push manual button , it goes all the way down.
What the heck is going on.
PIA.

Jim