Do you have a Vivi Nova? I am asking because of a mention of this issue on YouTube.
I have a Davide and it allows both flow from the little side holes in the neck of the 510 OR from the hollor core of the 510 connector. One review on YouTube mentioned that Vivi Nova didn't do this. Or something to that effect. Given my newness to the topic I must have misunderstood. But I was given to understand that the positive connector in the 510 connection was solid and that air had to come from the mini holes in the neck.
To further answer your question, I have been told that many 510 batteries (fancy kinds) are not passthough, the 510 connector is sealed so no efluid can get inside. Some reviewers mention that if you screw down tight on some units you block the flow some or a lot. The miniature holes on the neck are there to provide a auxiliary source of air. Some have even enlarged the mini holes in the neck.
So I being new want to know since this passthrough is required for my particular project need.