Refreshtoken fails when scopes are omitted

[filip8600]

When i try to aquire a fresh token with a refreshtoken based on the example, the request fails:

  B2CAuthEntity(
    refreshToken: _refreshTokenController.text.trim(),
    userFlowName: aadB2CUserFlowName,
    tenantBaseUrl: aadB2CUserAuthFlow,
    clientId: aadB2CClientID,
  ),
);

The above call results in a null-exceptions from the map method.

If i supply an empty scope, the request works:

  B2CAuthEntity(
    refreshToken: _refreshTokenController.text.trim(),
    userFlowName: aadB2CUserFlowName,
    tenantBaseUrl: aadB2CUserAuthFlow,
    clientId: aadB2CClientID,
   providedScopes: "",
  ),
);