I have always had sinus and allergy problems....so yeah I don't usually have much of a sense of smell, nothing to do with vaping though
I mean it could possibly be due to pg or vg, maybe it's upsetting your sinus' but doubt it....
if your sinus' are messed up your smell will be messed up, which usually then your taste is off a bit as well
need to talk to your doctor because there are health concerns that can cause this...my grandmother had no sense of smell at all, I forget what caused it though but it happened when she was a kid.