The maximum range of the skill seems to be calculated based on where you’re standing at the time of shot IMPACT, not when you fired the shot.
Conventional wisdom would seem to be that once the projectile is launched, it no longer matters what the launchee moves to, but that’s not the case with Combustive Shot.
This bug is easily reproduced, pick a fixed point, stand at 1200, fire a combustive shot at said point, while remaining perfectly still. Observe the location of the field. (Use fury sig or zerker stance for easy adrenaline).
Now repeat, except this time, dodge roll backwards twice while your combustive shot is airborne. The firey shot itself will continue to its destination, but notice how the impact and the fire field will be applied at 1200 range from where you’re standing NOW, and NOT where you were standing when you fired, or where the projectile looks to have landed.