Weird, but recently my mflb has just started tasting like shit, leaving this nasty taste in my mouth. Anyone?
maybe the trench is (near) finished? maybe you cleaned it and all the iso wasn't evaporated off. maybe you vaped something else other than MJ in the box. maybe your weed is low quality? pack a few more trenches and if the bad taste is still there, I would contact magic flight.
Make sure the MFLB is empty first, use the brush to get rid of any left over buds, then put your battery in while the mflb is open then proceed to gently brush your mflb for 5-10 seconds, the heat from the battery plus the brushing will get rid of any gunk that's built up on your screen, I do this quite a bit and it works like a charm. Just make sure to not leave the battery in for to long, 5-10 seconds works.