Yep. Surprised me too. At first, I thought she might be getting sick, and she doesn't seem fully broody yet (no pancaking. But she's pretty flighty, so staying on the nestbox while I'm in the coop is a strong marker).
I have eggs I want hatched, so I'mma see if she sticks to it.
I've got a barred EE mutt who was hatched from my own stock in spring of 2016. She's been clucking broodily all week, and she wouldn't get off the nest box this evening.