I am shooting in 1080p 60fps. Stop video to take some stills. Resume video. When I put the sd card in my pc there are two video files as expected. When looking at the file info I see the first file is at a bit rate of 26Mbps and the second files is 60Mbps. Today I shot one video and it is 26Mbps. I know they are different bit rate by the file size/minute. Nothing was changed. All previous video was at 60Mbps. What happened?