Does this functionality still work?
The import file doesn't create a custom field and the Field/Value pairs are just placed into the Notes section as if it wasn't specified in the original conversion command.
I'm using what I think is the latest version - 2019-05-22-2109
I've tried from both Windows and macOS but still the same outcome. I've also tried a new data export in case that was the case but still it all ends up in the notes section.
1Password Version: Not Provided
Extension Version: Not Provided
OS Version: Not Provided
Sync Type: Not Provided