Probably just wet fuel like mentioned or could've been some bad wood. Maybe it was the meat? Or something in the rub or marinade?
I think its safe to assume that with so many other variable it wasn't the cooker. Try a couple other cooks and see if the "tang" is still present.
18.5" OTS, 22.5" OTG, CB Silver(Rip), Vintage Coleman Bullet, Pit Barrel, UDS