This was posted on the Roaster's Guild members board. Thought I'd toss it out here, too, to see if any of you have ideas on this. If you do, please email Emily at emily@cafeimports.com
Thanks!

Hello, all.
Hoping that some of you can shed light on a problem we've experienced in the cupping lab. We have some theories, but are hoping that someone knows the answer to this...
Lately, we've been noticing that some of the grounds are falling before the coffee is even set to break. Sometimes this will happen on just one of the cups of a given coffee, othertimes it happens to all of the cups of a given coffee. It seems to happen most often (that we've noticed) on naturally-processed coffees.
Is this a water issue? A processing issue? Soap residue on the cups? Grind? Combination?
If anyone else has experienced this problem and can shed some light, it would be greatly appreciated.

Thanks!
Emily, Cafe Imports