With the new photos there does seem to be a small depression. Possibly pipe mud underneath the cake? Just conjecture on my part. I would take some sandpaper, like 220 grit, piece 1”x3” and wrap it around my finger. Leave a bit sticking out past the end of your finger, so it can collapse inward and conform to the end of your finger. Work it around gently and remove cake from the bottom. Then you can see what’s under that spot.
Or you could just dab a little maple syrup on the spot and smoke it. That’ll allow carbon to cover that up and it shouldn’t be an issue, unless it’s a soft spot, which may get bigger down the road.
Just start slow like your breaking in new pipe.
Or if it’s of concern return it to SP.