If you resummon skeletons with one dead, it breaks the cap of 5. That’s the bug, as far as I can tell, and it works with archers and regular skellies.
So if he just keeps casting it every 60 seconds, skeletons can accumulate.
It’s actually rather hard to play without getting a few extra, as their HP doesn’t regenerate under any circumstances, so even at bees he’ll have to start casting the ability - and if he loses one, the limit breaks, and he’s suddenly got 9 instead of 5.
If he goes down to 5 due to skeleton death, the cap is fixed temporarily - until he’s below 5 again. It’s pretty silly.
As it has been hinted before, the AI for the bugged skeletons is dysfunctional. Sometimes they stand idle for long periods of time. They can be encouraged to attack again with by moving far enough to leash them, but this trick won’t take even the most ruthless exploiter very far. They’re quite helpless against the new bosses.
It was this revelation - that my class was broken beyond repair even with massive bug exploitation on my side - that made me uninstall.