Moodle 3.9.2+ (Build: 20201103)
(Edited - see below)
Hi, I have a somewhat similar problem.
As an admin, I create an event, everything is fine until I change the event type to "category event". And then poof, the even completely vanishes from view.
I tried setting myself "manager" and "course creator" in this category, to no avail.
Is there any way to retrieve this event, if only to delete it?
Edit :
It appears it is a strange bug. I was tempted to say a display bug, but it goes beyond that.
As admin: If I reload the page, nothing changes. But when I add a new "site" event, then both the "category" and "site" event suddenly become visible.
The really weird part is that I am connected as student on another browser. There also, the "category" event was invisible, no matter if I reloaded the page. But after Admin added another event, then both events became visible for Student also. So, this "display" bug also has an impact on what other users can see.