by Russell Thomson.
I installed Moodle myself from scratch on the web hosting database. No one button click installer. I have upgraded Moodle regularly, the last upgrade being from 3.7.2+ to 3.7.3. I've never noticed this before as I normally backup with Filezilla. With Moodle 3.7.3, I tried to change to https but did not like the results so I restored to the point before the change, Moodle 3.7.2+. However, I maintained both databases as I can install up to 4 in the hosting service. I had done some 20 hours of work in Moodle 3.7.3, which I am now trying to restore into 3.7.2+, hence I came across this problem. The problem exists in both databases.