King of Mist Reward disappears after death (in cruel difficulty)

Hey Everyone,
Yesterday, I killed the King of the Mist in the cruel difficulty. The second I killed him, I was killed by a DOT effect, and once I respawned the rewards were gone and I couldn't acquire the permanent spirit buff. This is quite frustrating, and I tried looking for solutions online. I was able to continue the quest, but could not get rewards at the boss arena. After having killed KoTM and respawning, I was unable to teleport out of the boss arena, indicating there was a flag in the game code that he was still alive, but I couldn't kill him.

Hopefully someone can help me.

Thanks,

A New POE2 player

King of the myst in cruel does not drop the spirit buff. You will get the spirit buff from the act 3 cruel.