Rising Resistance.

[Leni]

The only time I've had that was when the 510 pin needed a clean. With the design of the X it's also possible to unscrew the coil when you unscrew the top cap. I find it's fine if you screw the coil in firmly, then don't over-tighten the top cap. Ideally you want the coil still firmly attached to the base when you fill the tank up.

 

[Deaf Vaper]

I have that same tank, but use a 0.8 ohm coil in it, the resistance does vary over time as the coil is used, but not as much as that. But the coil does have a habit of coming off with the cap, so that might be part of the problem, as juice may seep into the base and effect the connection of the coil itself. I do take all my tanks apart and clean them periodically, check all the seals, and make sure everything is screwed together properly.

 

[Lung Redemption]

Check your connections are secure and free from juice. I see this sometimes but mostly RTA related issues, aside it's usually the connection not being fully made(at the 510 connector) or some juice build up.