Agree with Minnesmoker - it's likely to be finely ground plant matter rather than keif.
I, too, have a keif-catching grinder and have smoked countless pounds of crappy 'street weed' in the UK over the years. The weed I used to buy was usually bone dry, and would essentially crumble between your fingers. Passing it through a grinder would fill up the keif chamber super quick. Like the stuff you're describing, it looked ok, albeit dry and crumbly, and wasn't particularly fragrant, nor was it sticky.
It makes me wonder what these cats are growing, and how lazy they are about managing it. It isn't much (if at all) harder to grow a decent strain instead of the bland junk they're putting out. Setting up my small, personal grow was a no-brainer. I don't even check my keif chamber anymore - I'm usually way too baked to be dealing with that noise.