This sounds like the switch contact wire shorting to the body when the protruding part of the wire is pressed hard against the battery tube, as when the battery tube is screwed all the way in. If this is the case then replacing the switch alone will not help.In the past (a couple days ago) that would have been defined as working 100% normally, no un touched triggers of the light (which I why I got a new tail cap from Henry, my previous one did that anywhere) now, its graduated to with a button locked light, doing the triple flash to indicate a press when locked, and not operating at all when fully screwed in. I should also mention that when the button is unlocked and fully screwed in, the light behaves like the button is fully depressed, (jumping and staying to my set click press hold level that Henry designates as high from the factory) Rather odd. :shrug:
This were my thoughts about the design from a while back:
"Looks like a solid design for the switch signal, much better than the spring used in the HDS/NT lights. Only slight concern one could have is that the isolating anodize might eventually be rubbed off thus creating a false switch contact. But anodize is very hard anyway."
Maybe you have missing anodize in the battery tube near the contact wire...