If you replace your hero with Ragnaros when you have Ice Block's immune effect, Ragnaros is still immune to fatal damage

[Kybxd]

https://www.bilibili.com/video/av52068925 (6:28 to 7:54)

[troggnostupidhs]

Video shows Ice Block triggering and then the Hero being replaced by Majordomo dying. Rag can be attacked, target by spells, damaged by spells, and targeted by the Hero Power. Even though the Immune effect is not displayed, Rag's health does not go below 1.

[Jetz72]

https://us.forums.blizzard.com/en/hearthstone/t/bug-with-ice-block/27791

Hello! I found a bug with Ice Block. I used Maiden of the Lake, Coldarra Drake and Majordomo Executus to use hero power of Ragnaros repeatedly. First shot dealt a lethal damage to enemy hero and an Ice Block activated. Second shot killed the enemy’s Majordomo and following hero powers haven’t dealt any damage to the enemy’s hero, while my creatures could still deal damage.