Thanks for the replies.
DEC - the yeast is Wyeast 1018 (Irish). I tend towards an earlier secondary than most on this forum, and I've never been disappointed, but more time won't kill me. The thing is, I doubt the yeast has much to do with it - the separation was there before and after...
I put up a batch of "Breakfast Stout" (Oatmeal and coffee) last week, using a partial mash and steeping process. The wort got jostled and stirred up after cooling, but before pouring to the carboy and pitching. Highly active fermentation (thank you blow-off hose) lasted for a few days, then it...