Well this is definitely weird! I’m on Linux too, using the AppImage version I get this:
{content: Blob, fileName: '/home/baj/Downloads/The goddess of fate..json', content_type: 'application/json', json: {…}}
content: Blob {size: 860384, type: ''}
content_type: "application/json"
fileName: "/home/baj/Downloads/The goddess of fate..json"
json: {total_rows: 68, offset: 0, rows: Array(68)}
I’m a little lost on what else to test, seems like the app cannot open the file to read its content for some reason, or the file is corrupted. If you create a test project, export it (Backup Database) and import it, do you get the same error? Thanks!