Because it is now after April 15, the deadline for making a corrective distribution that would make it as if the excess contribution had not been made, you cannot now obtain any corrective distribution to avoid double taxation of the excess. The "penalty" for making this excess contribution is that the excess and attributable earnings will be taxable when distributed, even if the Roth account is qualified, which is why there is double taxation of the excess. Because they are taxable, they will also be subject to a 10% early-distribution penalty if distributed before age 59½. The first amounts distributed from the Roth account containing the excess will be the excess and the attributable gains until the full amount of the excess and attributable gains has been distributed.
You probably need to inform one of these plans that you made this excess contribution so that they can track the excess contribution and attributable earnings so that they can properly report it as taxable when distributed. Normally one cannot receive an in-service distribution from the Roth 401(k) or Roth TSP account before age 59½, but that may not be the case for excess contributions; you would need to ask the plan. Since you nor longer work for the employer with the Roth 401(k), you could take a distribution from that plan instead. If you do not inform one of these plans of the excess contribution, so that you can report the correct taxable amount of any distribution that includes the excess, you'll need to track the excess and attributable earnings yourself which could be extremely difficult. Given that you can now take distributions form the Roth 401(k), it probably makes sense to treat the excess as being in that plan if that plan will agree to doing so.
See T.D. 9324 2007-22 I.R.B 1302 for details.
