Bug Report ID: #2914488603 - Zolin resurrects when returning to arena via portal

Today I experienced a resurrecting Zolin.

After the fight I had to go back to town to stash my loot, so I opened a portal in the arena and got out.
When I returned, Zolin would suddenly rise and continue the fight with 0 HP and full shield. I could destory the shield, but he wouldn't die again.
I could also open another portal and leave the arena with him following me a bit.