The wood I see in some of your pics looks somewhat similar to stuff I cut that can be hard, dry and even a sharp semi chisel chain won't cut nice chips but more like milled flour
. I have a Dolmar 6400 & a Solo 681 and use the flocked filters. My 681 came with the nylon filter when new and it would coat the intake with fines pretty bad. I stopped using the saw until my flocked filter arrived it was that bad. It would work well in other parts of the world I guess, they like the nylon filters where it snows apparently.