I've only ever experienced this bug when working with mpeg NTSC files. It doesn't seem to handle 23.976fps files if the pulldown hasn't been removed first. Things may look ok in the timeline but when rendering it screws up. It seems as if it misdetects the pulldown when rendering which results in the added frames. This doesn't happen when using lagarith avi though because the pulldown would have already been removed and you're editing at native 23.976. Plus, if you use the lagarith codec you can render out as an an avi file, using the same codec and settings as your project, and it will only re-render the frames/ sections that have had any effects or changes done, so rendering time is significantly cut. Use an external Mepg2 encoder to encode your final video as sony's is pretty lame. I would recommend using procoder3 as this gives the best picture quality than any other mpeg2 encoder that i have experienced, including CCE