OK! I finally got an actual taste! It is barely there; and it disappears very quick, almost like a ghost flavor, but it is definitely a taste.
It came from a double-extra-flavored coffee at 80/20 PG/VG.
The fluid is strong enough to smell through the bottle and left my tongue a bit raw after a few hours of vaping.
BTW, I just remembered something that might have a bearing on why it's difficult for me to actually taste the flavors. I may have a condition called geographic tongue; I know my daughter has it, (her dentist told me last year) and that it is hereditary. I also know that I have a fissured tongue (my dentist told me that ages ago) which is often associated with geographic tongue.
I also know that inflamation of the taste buds can occur with this condition, but I can't find any link to reduction in ability to taste. Hmmmm...
Well, I still have a dozen or so DXF flavors in this shipment to try out. I'll let my tongue rest tonight, and try a new flavor fresh tomorrow!
Thanks again everyone!