Chaos Wastes - "Downed allies are invincible" perk causes a stalemate

That has been a bug ever since Chaos Wastes was introduced more than a year ago, and has been reported multiple times. It’s a Morr’s Protection bug and/or a Miracle of Isha bug.

Morr’s Protection: Downed teammates near you are invulnerable.
Miracle of Isha: When the last member of the party is knocked down, Isha restores their HP to full and strikes down nearby enemies.

Reports of this bug:

https://www.reddit.com/r/Vermintide/comments/nk1slp/miracle_of_isha_not_working_properly_in_chaos/
https://www.reddit.com/r/Vermintide/comments/xc3bwq/it_turns_out_that_immortality_can_sometimes_be_a/