Are you toward the end of the battery charge cycle?I think the TC on my older Jac(12/17) has gone haywire. After vaping for awhile the vape starts to fade like maybe the wicking was not keeping up and the tc is backing it off. So I rebuilt a few times to see if I could improve the wicking, no luck. It would vape fine for awhile, then start backing off. I finally turned tc off, and went wattage, and it's been fine since, about 3 days now.