Per the linked conversation, it is most likely do to the @ symbol, and for context inside the dynamic dns section is says: Cloudflare, Linode: Enter @ as the hostname to indicate an empty field.

I've found a way around by:

1. Setting Host Name Resolution to Interface IP Address
2. Outputting the blah.ovpn file
3. Opening the file, replace the IP with my_domain.com
4. Saving + Importing

This works for me. I just wanted to document this in case somebody else runs into this same issue.

Still, if this can be fixed it probably should be. Could somebody point me into the direction of the plugin's repo? I've looked around for it but couldn't make heads-or-tails on where it is and where I would make an issue.