Hi Gust,
confirmed. Perhaps, given this is a problem that will certainly occur in the future, you could specifically check for these problems during conversion and either delete or replace them with a flag - maybe "BLANK"?
Also, and I don't know if it's a problem specific to my installation or Win11, NWCCONVERTOR can't seem to remember how to open the MusicXML file with Musescore. The correct path is in the options screen, but if you press OK, the config file is updated without the entry, UNLESS your browse to it beforehand. Then if you press OK the config file is saved with the correct path and it all works until next time you run NWCCONVERTOR, where, even though the correct path is in the config file, NWCCONVERTOR ignores it and you have to browse to it again...