The doors each have a door-catch. Its purpose is to provide two distinct positions where the door stays partly open, and one for fully open. The rubber grommet that makes it stop in the pinched areas of the catch wear and make the door failing to stay open. A bit of a hassle as these wide doors are quite heavy.
The door catch needs a lubrication from time to time.
To replace the door catch, the liner of the door needs to be removed. Then you can reach inside to hold the catch with one hand. With the other hand you can undo the two imbus bolts that hold the catch to the door. These bolts are accessible from the exterior side of the door, see picture below.