We could reproduce the bug you mentioned.
If you use the High-speed mode, Bandicut adds 2 sets of video header information.
However, sometimes Windows Media Player in Windows 7 doesn't recognize the new header information.
Unfortunately, we don't have a good solution for this issue at the moment.
Please try the solution below until we solve the problem.
1. Download LAVFilters from https://github.com/Nevcairiel/LAVFilters/releases
2. Check the "LAV Splitter (x86)" option (You don't have to check other options.)
3. Check the "MP4/MOV" formats (You don't have to check other options.)
We're sorry for your inconvenience.
The Bandicut Team