Comment 1 for bug 1981726

Re-scanning the library won't do the job. You need to reset all the information (ot at least the waveform, I suppose) related to that file. In any case, if you change the file also the key, BPM and replay gain might be different, so I think it's safer to reset everything.

Anyway, I agree with you it would be nice that Mixxx detected the new file and reset everything which is stored in the database.