The jump is normal where he jumps up and pounds the ground with an aoe. He just didnt come back down. Happened 2 times then i didnt stick around any longer. It was not my first time farming him
He completely disappeared off screen and didnt come back. And as in you quoted, it happened 2 times. With it taking 10min for the portals to respawn again, i didnt wait for a 3rd time for it to happen