I have a small mark in the top right hand corner of every video I shoot now. It's always in the same place same size, never moves, when I watch the vid using Windows I can see it. Cleaned the Gopro lens with a spectical cleaning wipe but it's still there. When editing in Premier the mark is evident but when I take a screen shot and look to edit it in photo shop it's gone! Any ideas what it is? I am formatting the SD card at the moment but have opted for the long format and it's taking a while.... Will try another card as well.