I've been processing a series of skyprobe images taken in May and in April 2011.

Prior to April 6th, 2011, they look ok: the flat is ok, they look nice and flat. (example, o5655i0118o02, processed through cam)

After April 6th, they look odd. They look like this from the raw fits files, too. They have extra streaks, and the flat isn't quite right. (example, o5657i0001o01, processed through cam)

After May 17, 2011, they go back to normal. The logs indicate that they fixed the focus on skyprobe - the weird artifacts and flat effects go away.