by Helen Foster.
Hi David,
I tried searching in the Moodle Tracker for a report of the problem but couldn't find anything, then tried to reproduce it on the Moodle Sandbox demo but failed - the activity was available but not shown on course page in the restored course.
How about trying yourself to see if you can reproduce the problem on the Moodle Sandbox demo? If so, then it can be investigated by developers. If not, you'll need to look at what might be the cause of the problem on your site, such as a plugin or customised code.