[2020] Re-Animate Global event Day 2 challenge not being counted

OK I notice that some of the challenges are not being counted most of the time and it is just making it tedious. Like this day 2 challenge of burning re-animated hostiles, I light them on fire but it doesn't count. I have it tracked and every time I light a re-animated NPC on fire and he dies the counter stays the same. I wait for the npc to fully get back up before burning them and after they go back down nothing. Only certain burn would count but I don't know what. I used the chem launcher, the fire turret, and the flame thrower and they all don't seem to count. The Imperial dynasty doesn't count either. So how am I suppose to complete this challenge?