To fix it, I replaced the "upper hinge cam riser" on the freezer door. I found small pieces of black plastic matching the appearance of the part that had fallen out of the hinge, so I had some idea what the problem was. Finding the replacement was easy thanks to your website.
The repair took about 30 minutes in total. It would take 15 or less if I had to do it again. In the end, it was very easy. Most of the difficulty was in the awkwardness due to the size and weight of the freezer door.