I have been having problems with the preview window in OBS 18.0.1 (Win 64) showing content slightly different from what actually appears in my streams and recordings. As you can see here, the OBS preview window shows nothing but the outside scene, but when I look at the recorded product (below) there is a black bar at the top and it appears extra content in the window was being recorded.
Why is the preview window not showing an accurate version of what is being recorded? How should I go about troubleshooting this problem? The only relevant setting I can find is Edit > Preview Scaling which is set to "output (854x480)", which is the correct size of my stream; VLC also reports 854x480.

Why is the preview window not showing an accurate version of what is being recorded? How should I go about troubleshooting this problem? The only relevant setting I can find is Edit > Preview Scaling which is set to "output (854x480)", which is the correct size of my stream; VLC also reports 854x480.