okay... I opened one up...
The two holes on the bottom aren't in a position to kill the carto by pushing a needle in... that was the 1st thing I looked at. I can't see that it matters, though. The air tube only sticks up about 1/4" into the carto.
Sticking anything up the center tube could deform the atty coils, but probably not seriously.
If you were to take one apart, you've got a sheet of wadding wrapped around the coil assembly. The coils themselves have some sort of pad between the coil wire and the wadding.
I looked at the fillinator vid, and the one thing that doesn't seem to jib for me is that there is no tube running the length of the carto, but I can envision how it would act like there is a tube.
I've been filling these by using a syringe/needle (always been my preferred method). I work the needle between the tube and the wadding and slowly injecting liquid to saturate the wadding. I'm trying to picture if filling from the inside out could be an issue that filling from the outside in isn't.
I'm also wondering if those pads around the coils (transfer pads?) could be over-saturated. They're not the same material as the wadding... more of a cloth-like material.
Your thought that you were blowing liquid out of the filler is a good one, and I suspect that you were indeed doing so. But it wouldn't clear those transfer pads... they're gonna hold on to liquid pretty well.
Another thought I had, but you already addressed, was to check that the center connecter extended a bit beyond the bottom of the threaded bit.
I'll replace the dead cartos, of course.
Do you have access to a syringe/needle? The needle gauge doesn't seem to be an issue... not too big of a bore, though, as that would be hard to work in between the tube and the wadding... I'm also going to grab one from this last batch I got and try it... the possibility that there's a fault in construction cannot be ignored.