FieldConfigArgument descriptions are not used in GraphiQL

Given the following configuration:

Args: relay.NewConnectionArgs(graphql.FieldConfigArgument{
    "fromDate": &graphql.ArgumentConfig{
        Description: "From date value with `YY-MM-DD` format",
        Type:        graphql.DateTime,
    },
    "toDate": &graphql.ArgumentConfig{
	Description: "To date value with `YY-MM-DD` format",
	Type:        graphql.DateTime,
    },
    "status": &graphql.ArgumentConfig{
        Description: "Current invoice status retrieved from transactions",
	Type:        invoiceTransactionStatusEnum,
    },
}),

The custom descriptions are not passed to GraphiQL.
For example, the type graphql.DateTime has its default description that is not overrided from my custom description. Indeed, they keep the default description:
The DateTime scalar type represents a DateTime. The DateTime is serialized as an RFC 3339 quoted string

Instead, the field status which is a custom enumeration, comes with No Description.