Description of problem:
Go to Web UI -> Content -> Subscriptions -> pick a subscription with role, "Red Hat Enterprise Linux Server with Smart Management, Premium (Physical or Virtual Nodes)" is a good candidate -> Details tab

Under "System Purpose" section, role is empty.

You can also reproduce via rest api:

curl -v -k -u "username:password"  https://satellite.example.com/katello/api/organizations/1/subscriptions/<subscription id> | python -m json.tool
{
    ...
    "roles": null,   <================== Role is null
    "support_level": "Premium",
    "support_type": "L1-L3",
    "type": "NORMAL",
    ...
    "usage": "Production",
    ...
}