Bug with refreshing Auth Token

[alagu]

When I do a client.refresh_access_token!

I'm getting a invalid_request error. Any help regarding this?

OAuth2::Error: invalid_request: Client must specify either client_id or client_assertion, not both
{
  "error" : "invalid_request",
  "error_description" : "Client must specify either client_id or client_assertion, not both"
}