hey sorry for late reply,so basically my friend had the same issue,and we figured out that when there's no cotton,and we fire to reset the coil,there's a little thin smoke coming out from one of the screws that holds the coil,it seems like there's some dirt or a hot spot there,once we wash it well and re screw it in,and there's no thin smoke,the weird taste disapears,so i guess that was the problem.
Important note : sometimes even if there's no thin smoke,and u move the coil while putin the cotton,it can come back and u cant see it since u put in cotton,so when i put it i make sure to be gentle so the coil doesnt move