Another member had the same problem and was told that the leak that you are talking about was not a defect and is not supposed to be an airtight connection.Also that the leak would not affect the persons therapy.
I believe that they are correct about the small amount of air coming from the elbow will not affect your therapy.....unless
the noise from the leak bothers you like it did for me and another member.
Not to worry because the solution is quite easy.
Take some heavy sewing thread and wrap it round and round as many times as you can in the space where the elbow meets the mask.
This also works for the other swivel connection further down the elbow.
The best part is that the swivels will still swivel and there will be no air leak at all.
Life should NOT be a journey to the grave with the intention of arriving safely in a well preserved body, but rather to skid in sideways, chocolate in one hand, martini in the other, body totally worn out and screaming,WOO HOO what a ride!