Invincible bosses

So now, two times on king of the mists (out of 3 attempts)

And 2 times on the crow bell boss

They enter a state where they bug and are invincible. For King of the Mists he just stands there doing nothing. Crow bell well refuse to go to phase 2. This is super annoying. Especially since I'm losing 150 splinters each time King of the Mists does this....