I see the exact same “too light to feel” stuff coming out of my cyclone. I suspect your cyclone speeds are SO high that turbulence is occurring in the dust sump and the particles are coming back out. I would hang a Mason jar under the cyclone and see what happens. I don’t ship cyclones with Mason jars because of the flying shrapnel liability in a sneeze, but I can’t imagine running without one.
Shall I send you a pair of “pipe flange couplings”? What you do with them is your responsibility.
I fill a quart jar every hour so I am also wondering if your cyclone is overflowing.