My Edge has 9K miles and has recently been serviced for this "burning smell". A repair was made for a rear axle seal. My car was at the dealer for almost 2 weeks because once the repair was started, another part was needed that was hard to find. The bad news is that my car is still smelling/burning, and a few times whitish smoke has come in through the vent. (once while switching drivers on the turnpike)
I will follow up today with them since I know know that this is not an isolated incident with just my vehicle.
My Edge needed the PTU replaced also. Thanks for all the information available on this website!