Last week, I pointed out a lot of immolation spirits sticking around. Those are better, but there's still cases where companions can be leaked (left around) on the server even after their owners leave. This can't be free for server CPU/RAM load, network bandwidth, etc. These screenshots were taken Sunday May 12th, ~2:30PM Central at Dread Ring instance #1, entry campfire. I dismissed my companion for these screenshots. I've not blurred out the companion names - I didn't see that as something too personally identifying.
It's the same 3 leaked companions highlighted in these pictures, just different angles to catch each of their names.
And, instance info: