Thanks for reply !
Sorry if I wasn't clear.
I have 7 concerts (initially all different of course) with 1 song.
The problem is that the song of one of those concerts has replaced the one of each concert. So now I have 7 concerts with the same song...
With screen captures :
1. NINoN concert with the song 1 - Ninon.
2. go back to concerts list
3. I choose the concert Piano, and the content is again Song 1 - Ninon from NINoN concert. And that's the same for all other concerts.
I tried revert concerts ( as you suggest). No change
I tried to erase the database file in preset folder (db.db3) for update. It updates well, but no change for concerts problem.
Hope It's more clear