I've been finding silicone coated fly material to have less of this problem in being stuffed long term. i've got some silicone and PU coated nylons of similar vintage lurking in my gear tubs.
The PU coated nylons are sticky and in the process of breakdown, powdering or otherwise separating. The silicone nylons, similarly stored, seem more stable.
This has been my non-scientific observations of silicone vs PU coated nylons over the long term -15 years. YMMV.
This thread reminded me to fluff and look at the gear in the tubs that i haven't been using regularily.