I use conduction vapes and I dont get a burnt popcorn flavor, ever
Well, that's good. Seems experiences of many others are different, though. Maybe it's your material or you're vaping at lower temps? Or, maybe you don't get that same feeling of flavor from a spent load roasting? Think you said above it tasted more like Chinese food to you. I've never tasted that, so maybe just a difference in taste buds?
I don't think it really relates to conduction/convection itself as much as convection will usually only roast/vape while you are hitting it and conduction will often cook whether you're hitting it or not, causing higher temps in the vape oven. IME convection will only go to a certain set temp because of this, and when vapor is done, we stop drawing so no more heat added. With conduction, it keeps roasting (and raising oven temps) until power is turned off. If you keep hitting when spent and still heating it usually imparts a less pleasant flavor. For me, that flavor is pretty close to burnt popcorn. For others, I guess it is weird Chinese food or maybe something else. Whatever the case, I think it safe to say that conduction will do this more, and more often, for most of us on many vapes.
Not that conduction is necessarily bad, or convection is necessarily good. Think there are examples of good and bad with each on different vapes with different techniques. Personally, I definitely prefer convection, though.