Today I ran across a Hunter who spawned and disappeared here:
archived post about a similar occurrence happening to someone else. Same area and all that.
Now for the Game Theory.
I've been playing this game for the better part of two years. Until recently when I started actively going after hunters, I had run into a hunter (unknowingly) all of 1 time, and promptly got wrecked.
But now that I'm going after hunters, I keep finding hunter spawns where they're not supposed to be. At the church next to the MLK Library, on this ledge, at the octagonal section of the haunted house control point at night, and at the Nest control point.
These hunters never fight me. They make their presence known, then they promptly leave.
My theory, due to the coincidence of it all, is that the game is having the hunters "keep tabs" on the player. Not in the literal sense, they don't have enough brainpower to study how you fight and adjust to it, but rather as an in game feature to keep you on alert, while also setting it up so that down the line they can introduce a new set of hunters that know who "you" are, because they've been watching from the shadows.
But that's just a game theory.