Did you use a multi-screen preview by chance? When the effective window size changes (as going from a split window to full window) the camera view is reset. A vertically split window with the full figure nicely zoomed will produce the darned headless-legless image when you just switch to a full window preview, even for the same camera. It seems to use window WIDTH to assess camera zoom, which seems less than intuitive to me for a figure pose, leaving a hand or arm out of the picture is often fine, but a head? Work around seems to be: switch to single window view manually first, reset the camera zoom, then render. Tiresome, but perhaps PP worked this way too?