Not from your side of the pond so I can't speak to the Appalachian stuff directly, but the pattern sounds familiar. We get similar clusters over here near Pendle - suddenly three or four people report the same thing in the same area within a few weeks and then nothing for months. Makes you wonder if something is actually moving through rather than just living there.
The Dogman stuff always gets me because the descriptions are so consistent across witnesses who clearly haven't talked to each other. That's the bit skeptics can never really explain away properly.
Anyone got dash cam or trail cam footage from the AT recently? Eyewitness accounts are fine but we need something more solid if this is genuinely picking up. Also curious whether the sightings are clustered around specific trail sections or spread right across.