I am experiencing the same issues as Dewald below, but I found that the box size fixes itself if you change the Image Scale size and return it back to the desired size.
The fact that I need to do this every time I open OBS is rather frustrating however, as is the problem of how often it reverts back to the original DVD screensaver logo completely forgetting the source I directed it to.
All in all, it serves the function I need it to, but the annoyance of needing to manually "fix" it every time I open OBS makes me question how worth it it is. It's certainly the least-buggy DVD screensaver option I've found, but it's far from perfect.