Moodle 4.1.14.
A teacher maintains a course with a large number of of H5P activities (mod_hvp black one) and quizzes, so far found only core question types. It is not a course which is conducted, rather a repository of content. Those activities are copied to running courses through Sharing cart.
The teacher discovered that one quiz can not be copied, it never finishes. Just to get an idea how heavy the repository course is, I made a full course backup without user data. It is 225 MB large. Not too bad for the sizes of courses (with user data) I see here. Then I started restoring it to a fresh course. I looked like that the restore was finished although it threw about three pages of warning link in the attachment.
It looked almost over but then from its own started from 0% again. And after an hour still at 98.65% Note that background course backups and restore are ON.
What should I look for to find the cause?
The server is a big iron dedicated server over-dimensioned for the work. I monitor everything in it, it never reaches 1/10 the capacity during the whole process.