I just thought of something while sitting here at work. When I tried using my hpa tanks, I would throw in a dummy 12gram instead of a spent 12gram. I wonder if it's a volume issue as I assume that others running hpa must have just used a spent cartridge. The dummy 12gram has little volume and must hold very little air. I will give this a try in the morning and report back to all.
This is really the only variable that I am changing.