OK, that log kept talking about container so it seemed different from what I know.
There are 2 slots for the supervisor. When you update it updates the one you are not using, then makes 3 attempts to switch to it. If it fails, it goes back to the working slot.
Search here in the forum for info about failed slots or words to that effect and you will see a lot of people working this problem. Tips on Searching for Answers & Duplicate Topics in the Forum