Stan only just now linking together bothersome weird little facts about the Jennings did work for me. Of course the writers held this moment back to the end of the series out of necessity, but the way it's all coming together now for Stan feels authentic to me. It felt like those time you hear about researchers who 'dream' the solution to their problem, or who seem to have an 'A-HA!' moment out of the blue after stumbling around a problem for a long time. All of the clues were percolating around in their head but their conscience mind kept pushing them away or not linking the clues together. Stan's observed little things wrong with the Jennings for years but ignored them because of his friendship with Philip. But the Harvest cast happening with both Jennings vanishing mysteriously was enough for Stan's mind to start putting all the clues together. I don't think he's 100% on to them yet, but the fact that they've risen back on his radar enough that he was willing to set aside his friendship and break into their house to snoop around is a bad sign.