Lumintop Tool AAA (xp-g2) acting weird

So, today I received the newer Lumintop Tool AAA, with XP-G2 led. I already had the 'original' Tool AAA (xp-g).

Straight out of the box, this new Tool AAA didn't work. Tried with Eneloops and Duracell Alkaline.
So I used my knife to check if the problem was the clicky or the led/circuit. With the knife it worked.
Then I thought, hee, what If I mix components with my original Tool AAA. And here is the funny-part. The tailcap/switch from my original Tool AAA works on both bodies/heads,
and the tailcap/switch from my new Tool AAA also works, on the original one. But screwing the new Tool AAA back together, and it doesn't work.

Yes, I already cleaned everything, tightened every part, tried different batteries and so on

What can it be?

Sounds like tolerance on something. If the threads are anodized, the body one light may not quiiiiiite reach the contact ring of the other before the outer diameter of the head threads bottoms out on the body. Or ghosts.

AnAppleSnail said:

Sounds like tolerance on something. If the threads are anodized, the body one light may not quiiiiiite reach the contact ring of the other before the outer diameter of the head threads bottoms out on the body. Or ghosts.

Click to expand...

That's also possible. That the battery-tube/body doesn't touch the ring inside the tailcap. Crappy QC in that case.