Never been near Blue Ridge myself but big black cats keep popping up in reports from all over - Dartmoor included, and I can tell you from personal experience that when you see something that size moving through the dark it absolutely rewires your brain for a few seconds.
The "it was just a dog" explanation drives me mental. Nobody mistakes a dog for that.
Worth checking if there are any ley lines running through that stretch of the Parkway - sounds daft I know but a lot of big cat sightings cluster near them, same as here on the moor. Could just be coincidence but the pattern keeps showing up in the data. Anyone got coordinates for the sighting? Would be curious to run it through a map overlay.