If you’re still experiencing this behavior when you attempt to start Roon on the new Core, I suggest you set aside the database with the following steps.
Create a Backup of your current database (if you don’t have one you want to use)
Reinstall the Roon App from our Downloads Page to generate a new Roon folder
Verify if the issue persists on a fresh database before restoring the backup
The tech support team saw some references to what appears to be another storage location in your Core diagnostics. Where are you hosting your local music library and watched folders - on the Mac Mini (Core), or another device (NAS, external hard drive, etc.)?
If the database refresh above doesn’t help with the issue, please send a screenshot of your watched folders from Settings → Storage and we’ll proceed from there. Thank you!