Native would be what the original format of the bluray your playing is (ie 720p 1080i, 1080p), without the BRP altering the output. can you try a different source to see if the problem still occurs? Not that the cable couldnt be a problem, but if it has worked prior it seems to be unlikely. Make sure your projector isnt doing any additional processing by checking your settings (a button pushed by accident ) also try the other hdmi input