So it would almost certainly be the brain itself, rather than tastebuds or olfactory receptors; sounds like the burnt taste just kinda confuses the neural pathways associated with taste/smell, so those parts get shut down, leaving you with a very incomplete "palate" of tastes/smells you can perceive. Now I wonder... have you ever been in any kind of fire, or fire scare?
The reason I ask... once we lived in a "mobile home", and you may know how fast those things can burn down; one morning I awoke to the smell of smoke, which at first I thought was burning leaves (it was autumn), but then identified as the smell of burning insulation/electricals... long story short, a fire was averted because I basically levitated to call 911 and get myself and my son out of there; the smell was coming from an arcing wire, which was arcing against a 2x4 rather than the thin panelling, THANK GOD... but now, if I smell ANY kind of smoke, my brain goes into full-on panic mode... I have to track down the smell, no matter what or where. It's a powerful association/compulsion, which I seem to be completely unable to get rid of. When I get a burnt taste from my vape, I do feel a twinge of that panic, easily dismissed because it's so obviously *right there*, but I wonder if something like that could be going on; the part of the brain that processes olfactory data is very close to the part of the brain that processes memory, especially long-term memory, which is why a certain smell can be very evocative of memory.
Andria