Yep. Probably the heat steeping it in the tank, especially if you don't vape it fast. I brought this up before in another thread and that was the general consensus. It's also partly due to the wick/coil gumming up and contaminating the juice.
yepper !
I truly believe this is true--just like cooking on the stove, same principal works here (cooking, vaping)
that's why I am working my way towards smaller tanks and in my bigger tanks, I don't fill as full...
keeps it fresh and unburnt -- IMO
bonus question : what is the smallest capacity bcc tank ?