Sometimes the liquid also leaks into the mouth tho very tiny amount (yes, this depends on the vape quality). And usually the liquid is mixed with glycerin, which has quite a high amount of calories. Worth considering if you fast for health benefits.
I guess the way you’re asking this it could be related to like if you lived somewhere super humid and asked if the water particles in the air are breaking your dry fast. I would say no. I smoked dabs during my three day dry fast to make it more tolerable but then I got told off by people because “dry fasting is for healing” which I agree, but meh. Just do what you feel is right and helps you cope IMO. is it weed or nicotine. Nicotine is crap IMO