Yeah, 100% vg dries my mouth out too, and as I previously stated, it's normal as it's hygroscopic, together with pg and nic.
VG, when used on the skin in e.g. a cream, will moisturize, since it retains water in the area(hygroscopic), but what happens when vaped; you blow out the vg filled vaper, and as vg will hold on too and retain water, then the moisture of your mouth is drawn out and exhaled into the blown out vaper. Besides this standard hygroscopic properties, then some can have extra sensitives to pg(about 1 in 100 or 1000 i've read), and more rarelly vg. Many, falsely thinks/claims they have pg sensitivities because of this normal drying out effect of such substances... Personally, I believe vg is a little worse for me than pg, as if I remember correctly, it's also the more hygroscopic variant of the two, but i've both gotten used to it by now, plus I much prefer the taste of vg over pg, so only ever
vape vg with water added, instead of pg, regardless...