I have the same problem noted on last weekend’s show with another Subaru owner. My car has a burning type smell (burning rubber or burning oil) only when driving uphill on a mountain road. I’m not sure the answer given on the show is correct about the rubber under the carpet smelling because of the catalytic converter. The smell comes through the venting system.
The clutch could be slipping slightly and this will give off an odd burning smell.
Set the park brake firmly, shift into 3rd gear, and while holding the foot brake also, rev the engine a bit (say 3k RPM), and start releasing the clutch pedal. The engine should die.
If it does not or seems hesitant to do so then the clutch probably needs to be replaced.
(Yes, I know the above procedure takes 3 feet.)
I’ve had the problem starting with only 11,000 miles on the car.