I know, bit of a necro...
Anyway.
Unfortunately joyetech has started to change the ego threads. They are slightly higher which is causing an issue with aftermarket items like the kanger t3
Doesn't surprise me. Every company that makes something involving connectors(cars, tablets, etc) would rather their customers use their stuff as opposed to 3rd party stuff.
It isn't necessarily an attempt to create a monopoly or force you to use just their stuff, it's more of a "we know our Product A works properly with our Product B"
I also figure it saves a company some R&D when a problem comes up that was caused by a 3rd party item(as in they don't have to try to fix what wasn't their fault)
Related: I have something similar with a mini-clearo I got. It works just fine on my regular eGo-T, but won't work at all on my eGo-T passthru *shrug*