I'm having the same issue with mine. It's interesting, because the first two weeks with my Boreas were completely leak-free. I can't seem to figure out why it's leaking out of the air holes like crazy. It only happens when it's on its side or in my pocket while sitting down. I've even tried closing the AFC/JFC completely and putting it in my pocket. It still leaks. I went on a brewery tour on a bus yesterday and the fucker just kept flowing juice into my jeans pocket. I got home and my underwear was soaked with juice. It's really disappointing.
I fill it as the directions specify and that doesn't seem to help. When I tip it over and close the top all the way, juice leaks out of the 510 tip, so I have to fill it, tip it, close it quick, open up the airflow, flip it back over, and vape the hell out of it instantly to avoid leaks after filling. Sometimes that doesn't even work though.
I was cleaning it a couple weeks ago and dropped an o-ring in the sink. I had no idea where it went, but I guessed it went into the bottom cap (small o-ring). Perhaps this is it, and it shouldn't go there? Is there a diagram somewhere that shows where all the o-rings go on this thing? I might just replace them all.