I would say i am 99.9% sure it is condensation which results in that gurgle feel.
Cleaning when condensation has built up (this creates a little leakage and gurgling because it is very easy for it to seep through the wick due to it's thinness being mainly water):
1) Remove base and put to one side (I remove the base because it lets the air pressure out and speeds up process 2). 2) Put your Evod on a piece of tissue drip tip downwards and leave for 2mins. 3) Clean up the mess after the two minutes and roll a bit of tissue and pipe it through the drip tip as far as you can go to clean up any excess condensation. 4) Re-assemble and you are good to go.