No, that's a different issue relating to step 2 of the upgrade process.
The issue raised in this thread relating to step 4 is not fixed.
The ticket was for an unrelated issue, but when they fixed that unrelated problem it also fixed this problem.
The subject of the ticket was "Error when updating marketplace app".
Thanks! Found a permission denied error there. It's too late to tell if I've fixed the permissions now because I went ahead with the manual upgrade due to the site being stuck in an "upgrading" state, but I'll try it again next time.