Win7 64bit nVidia Quadro 4000
Broken: 2.73a, 2.73
Short description of error
when having a scene in the sequencer, bpy.ops.render.render() will just produce an empty image. When turning off sequencer, it works as expected.
Exact steps for others to reproduce the error
Open above .blend - type bpy.ops.render.render() in console - you get an empty image and 0sec render time. Turn off sequencer in "post processing" and type the line again - render works as expected.