I re-made Nekros recently and have been on the hunt for High Noon, but I just noticed something strange when trying to Desecrate a Brood Mother...I couldn't. The corpse was very clearly sitting right in front of me, but pressing 3 only resulted in the "Invalid Target" message.
So, I went about the mission until I was able to reproduce this and it turns out that it's tied to the Brood Mother's death animation. If a Brood Mother just dies and ragdolls, you can Desecrate it. But, if goes