I thought it was a problem only with musescore 3 files in the app, but there was more:
1-I can't open any musescore file from another location (the app opens, the process is initiated but score doesn't appear) and
2-In Songbook I have + UPLOAD MSCZ FILE, I click it, I can select the location and the mscz file, but the score doesn't appear and is not saved in Songbook
The only way I can save a score in Songbook is to save it to My Scores in Musescore, open My Scores in the App and finally choose the option Save to Songbook.
Not an easy way to reach my goal...
Can you tell me something about?