My guess (and I appreciate that guessing is not really whats needed here) is that the plastic liner is split inside. The Carbon fiber wrap is not supposed to be airtight, its simple function is to stop the plastic (5mm nylon if I remember) "balloon" liner from expanding beyond its limits. This (in the video) from what I remember of Stako's description is it failing safe, where when the liner splits, the air is vented quite quickly but not explosively through the fiber wrap. It should obviously not be refilled, I know Stako were attending every millennium event last year, not sure this year tho, but if they are, go to campaign cup and give it to them. Failing that, Hpac I think have basically an endoscope to inspect the inside of tanks before they re-test them. Failing Stako, they should be your next port of call, and i would guess they have communication channels with Stako after the previous incidents.
I hope some of that makes sense and maybe is even helpful
