Support Final Challenge- Incendiary Launcher

This challenge is surely bugged:

To complete this challenge you need to get 2000 damage with the incendiary launcher which doesn’t sound too difficult until you realise it only counts the damage on a direct hit and not the splash damage caused from the weapon. 
The damage the direct hit does is way too low if this is the intended function for the challenge as it does around 15-30 impact damage and then up to 40 burn. 
I know that bot lobbies (portal) but I think that challenges should be something that you can do without portal and have fun doing them. However, challenges like this one promote doing them against bots instead.