Why do some buildings with automatic doors, sometimes having the doors staying open. Is there a reason to that? Since sometimes when I go in stores the doors are left standing open as I approach and not opening/closing?

And also, we went to Walmart today, and the “entrance” side door was standing shut as we approached and wouldn’t open. So the greeter, tapping the middle of the doors with a broom handle, and then she tried sliding the doors apart, and they came open but quickly started to shut, which scared her and she jumped back. But then the door started operating properly again, she said it had been acting up.

These doors get quite beating from the hordes of impatient shoppers, are not that much protected from elements, so no wonder something in the mechanism or electronics breaks from time to time.
Also it uses to be quite finicky to adjust the motion sensor to start opening in time and not causing delays, but at the same time to not keep opening at random jusg because some car is passing or a fwe leaves are flying around.
So the solution uses to be to just let them stay manually open at least during the rush hour.
And many of those stores just generally pinch pennies on maintenance...