Incinerate + Cast On Elemental Ailment

Hi I'm running a incinerate + cast on elemental ailment(snap + living bomb) and i think there's some kind of bug with this interaction. I start incinerate with full fuel and as it starts losing fuel the cast on elemental ailment with snap and living bomb starts procing and i get more fuel but the damage sometimes halts and starts to ramp again. I feel like this interaction its weird, it should not gain fuel or if it keeps getting it should no restart the damage. My assumption: Kinda of hard coded fuel limit time and since im generating more while channeling the spell kinda restarts the damage when it reaches the hard limit of time. The incinerate stage count always remains 12.