I'm experiencing this right now, although it has improved somewhat. I'm convinced it's related to the drying effects of PG in the nasal passages. Even if you think you are exhaling through the mouth only, some vapor will still get up into the nasal cavities. The sinuses need moisture to do their job effectively like being able to smell the wonderful vape additives. And since the taste sense depends heavily on the smell sense, flavors become muted or worse - changed (and not for the better).
I did a test yesterday and made myself sneeze. Sneezing usually gets me to produce some type of fluid/semi-fluid in my sinuses. I blew my nose and vaped about 30 seconds later. I wasn't surprised when the pomegranate actually tasted pretty darn good instead of the weirdness when I first cracked open the bottle last week. Since I don't have a sauna out by the pool or a pool for that matter, I've dusted off the heated humidifier and will proceed to spend a good 20 minutes directly inhaling moist heat. I'm hoping regular use will give me the results I want.
I should add that when I smoked analogs, I exhaled through my nose all the time. Also, I wear a CPAP mask for sleeping which forces air through my nose at a high rate of speed to keep my throat from closing. Even though I have heat and moisture added to it, the fact that it is like a reverse vacuum cleaner means that there is probably some drying out going on when I sleep. So, basically, I am at a disadvantage already.
