Ever since the Chimera update and the ogris bugfix "Nightwatch Napalm's napalm fireball origin no longer block projectiles" the napalm has not been working properly. The visual is still the same but the damage hitbox is now only the small ball in the center. I would imagine that these are related.
Poor example but it's hard to get them to walk into it.
Oh, and while we're at it, can you make it so the flames match the energy color? 😃 Please?