「EXCEPTION: x個中y個のアップロードがS3に移行されていません。'default'データベースのS3移行に失敗しました。」の復元に失敗しました。

I’m facing the same issue here but I haven’t been able to resolve it:

Could you explain in more details what exactly you did here? Was this settings disabled in the Admin → Settings GUI page or was it on in app.yml? So after the backup, you were able to restore it and get everything back? Did you turn on this setting again after the backup? Thanks