These are not quest-related mobs. They are there to be killed for XP and for gold. They don't have quest arrows pointing at them. Reloadui and logging off and on have not worked. I don't see other players fighting any mobs there which are invisible to me, so I assume that the mobs in that place don't spawn for them, either.

I just now examined the area that I indicated on the attached map in my original post, and I noticed something strange about the objects in that area. There is a tent that is not in its usual position. It has moved a bit to one side. Before this problem with the non-spawning mobs began happening (more than a week ago), it was possible for a player to run around the side of the tent, go behind it, and then back out into the room along the other side of the tent. Now, however, that maneuver is impossible because the tent has been moved so that it abuts the rock wall of the cove.

Again, I have not seen any other players fighting mobs in that area, whether or not I can see them myself. And Crimson Cove nearly always has several players using it to earn XP or gold. So I think that probably it isn't my copy of ESO that is the problem.

The ticket # is: 240822-011072

Here is another screenshot that might help.

The image shows Crimson Cove in Malabal Tor, facing the NE corner/recess of the eastern room on the lower level. This place is at the bottom of the drop off place from the upper level.