I find this a little more common with juices containing any VG. VG seems to kinda coat the mouth, and a good toothbushing helps. Aside from that factor though, I've posted several times about odd tastebud stuff, as have many others. Some seem to find a daily vape early on, and stick with it for months with little change, so I'm not sure this stuff is universal. I've been wondering about a good palate cleanser, someone mentioned bubbly beverages before, i was thinking non-flavored juice might work well to switch in/out.
On the water tip, I'm really quite amazed, and a little worried about summer. I always drink water. In fact other than coffee and booze, water is all I drink. I carry a quart sized bottle around with me everywhere. Usually this time of year it gets emptied once a day. Lately I've been going through 3, and thats not counting other water drinking. If this is proportional, active summer periods this year could see me drinking well over 3 gallons a day?!?! I think that is definitely beyond the point where plain water won't cut it, and something with electrolytes will be needed. Bloog gets a lot less convenient if I have to drag an IV stand around with me! Any active folks vape through a summer in a hot climate yet? Does this go away?
Just remembered Leaford posted recently that sometimes the flavor doesn't wick as fast as the rest of the juice, and just resting a carto for a few minutes will help. Evie, have you tried switching cartos of the same flavor to see if it is that effect and not your tastebuds?