To be clear, there is no age-55 threshold for the distribution from a Roth 401(k) to be a qualified distribution, only the age 59½ threshold. Separating from service with the employer providing the Roth 401(k) account in or after the year you reach age 55 is only an exception to the early-distribution penalty (which already would not apply to a CRD), not an exception to the earnings being taxable prior to age 59½.
