vincinator44
bcavnaugh
Brand New Swiftech G¼ Male-Male Lok-Seal Short Extension Fitting (11-18mm Range) - Black
You should never double stack an oring. If they designed it that way, that was a poor design.
Most do have 2 O-Ring Slots that is why their are 2 O-Ring. I have 5 Different Brands and all 5 have 2 Inner O-Rings.
Myself I did not stack them that is how they come.