I wonder if it is an interaction between a particular recipe and Whirlfloc. The reason I say this is I do not recall experiencing this until my most recent brew - and I always use whirlfloc. It should be said that I have only done 9-10 brews since starting last Fall. The recent brew where it showed up was a Zombie Dust clone.
The unique features for this brew were: lots of Citra hops (10 oz.), and Cara-Pils grain. Honestly it looked to me like hop sludge. I always use a hop-sack, which retains most of the hop material. But maybe Citra hops have a higher percentage of really small particles that excape the hop-sack?
What do you more experienced brewers think of this idea? Is it possible that the massive fluffy trub is due to a particular recipe ingredient?
Could be the recipe, though not necessarily the whirlfloc. When pH isn't low enough, you get inferior protein coagulation and hot break. Some of it probably is hop trub as well.
It *should* look like egg drop soup after flameout.