Flavor Wicks Scorching???

Hey all, quick question. I just started trying the Kanger ProTank 2. After every couple of tanks of juice, I go to clean it and dry burn the coil. When I take it apart, I notice that the flavor wicks are burnt. What could I be doing wrong? I keep it vertical during vaping, so I’m not sure if I am just taking draws from it that are too long or that I’m not giving it the time it needs to re-wick after each draw? I vape Boba’s (nearly 100% VG), so maybe I should be cleaning/dry burning after every tank? I’m using 2.2 ohm heads and vape at 6.5 – or 7.0 watts (if that is helpful information). Help. Thanks.