You do understand you now have to save in order for changes to be real?
Really sounds like your audio files are the problem.
And 2.02 is here, even with no bugfix this time; dzee asked me some questions and so it gave me an idea (second point of changelog).
Changelog:
- Now supports directly DSP and HSP files
- Added the option to consider "unknown" extensions as VGM files
Maybe upload your audio files somewhere so that I can see the behavior for myself.
python "C:\Users\...\_NUS3BANK Editor.pyw"