Artifacts stop working during Kyashatar fight in "Dragon in Chains"

ilsynd

I have the Orb of Shiv at rank 20. It causes creatures I summon to be affected by the Molten Shell spell. I noticed that none of the creatures I was summoning were showing the tell-tale signs of the repeated explosions that spell causes. It worked during the lead up to the final arena, but didn't trigger once in the final battle. It makes me wonder if there are other, less obvious, artifacts that are also turned off.