As one who spent an entire year of life working with a nutritionist to track down food allergies (and only being able to eat like 6 things for a month, and then add ONE thing back at a time).......YES.
Turkey and fowl allergies are not uncommon.
(What is bad is that many people spend their entire lives with migraines, or reflux or even asthma.......and later find out it is food, which is essentially, a chemical.)
So the PG VG Flavoring thing among vapers wasn't in the least surprising to me.......not even a little bit odd. The thing is that most people don't go "looking for what they're allergic to" (indeed, it is never even suggested) ..... but then they start something "new" like vaping and have all kinds of problems.
BTW, I suggest that if any vaper has sensitivities to anything in vape juice, there is a good chance there are other "offenders" in their lives.
(public service announcement)