Probably not leaking- it is condensation, wipe the inside of the cap every few refills.
Not where its leaking. I figured with the increased airflow, I would get more condensation on the inside of the deck. Mine is actually leaking at the bottom of the tank itself where the pin is. After I let the tank sit for a little bit and then unscrew it from the mod, on the bottom there is liquid. Which in turn, makes me nervous to use it on the Therion until I have all the kinks worked out.