A mob defeated by a Brimstone tick did not count for the mission objective

[Maloke]

This happened with the stalker version of Stone Armor. In the Tsoo mission of Heather Townshend, I fought Hua Tov in the opening room. He died to a tick from Brimstone, but the "Defeat Hua Tov" objective did not complete. This was discovered after the build that was deployed on November 23rd.