With the Holmes V2, some of them are leak-free, some aren't. The problem is the removable deck. It screws down with very fine
threads and does not use any o-rings, but if the threads aren't absolutely perfect,
juice will leak down into the airflow section, and from there, dribble out the airflow holes. An easy fix is to just use some plumber's tape (thread seal tape) on the deck threads. That will seal the leak.
Thread seal tape is non-toxic, extremely inert (it does not react with any of the substances in
e-liquid, and can withstand temperatures up to 500 F with no damage (but it will still work if it gets a bit hotter than that).