I don't think there is an exact science developed yet that explains vapor's tongue. I know I have had a couple bouts of it myself that last about a week.
Smell and taste are intertwined, so who knows what could actually be causing it. Perhaps it's a sinus related cause. Maybe a virus?, or perhaps it's environmentally caused?, or is it diet and hydration?
The hydration-electrolyte solution is the one that makes the most
sense to me personally. IMO it's always a good idea to include a balance of electrolytes in your hydration because the vast amounts of water some drink may be flushing the electrolytes out, possibly causing an imbalance in our systems.
I include the home-made electrolyte drinks (fresh citrus, sea salt, honey) in my diet hoping to insure a good balance.
YMMV
GL
Vape onnn...