Gotcha. I think I know what you're seeing.
Remember that I don't have a spray setup, so everything I do either comes from a rattle can or is brushed on? After taping off the f/b and spraying the black paint, I brushed on water-based poly. Instead of hanging the neck, I laid it on some riser blocks, f/b down. With the neck being curved, the finish tended to run a bit and gather at the edge of the f/b. It's currently thick & a bit gummy at the edge of the f/b in places. I haven't looked at those exact spots, but I'll bet that's what it is.
But hey... thanks for trying to look out for an issue I might have missed. I really appreciate it.