Cannot add cloud credentials because optional key is required in UI

I want to use an OpenStack Swift cloud provider to backup some data my TrueNAS Scale instance. With authentification v3, the WebUI (in Credentials → Backup Credentials → Cloud Credentials → Add) is requiring the key tenant_id, which is optional according to the rclone doc.

I am able to connect to this service by setting only tenant_name and tenant_domain using rclone on my machine, but the Web UI requires that I input something in tenant_id, which results in a failed authentification.

How do I force TrueNAS Scale to take my manual rclone config? And where exactly should I report this bug? Thanks.