Presumably this From 1099-R has code G in box 7. I would also expect box 5 to show the difference between boxes 1 and 2a. In the follow-up, be sure to indicate that yes, this distribution was rolled over to a designated Roth 401(k) or Roth 403(b), yes, you made after-tax contributions, and that the amount of after-tax contributions agrees with the amount in box 5 of the Form 1099-R. You should see on line 1 of Form 1040-X a net change of the amount in box 2a of the Form 1099-R.
Your federal tax liability might not change if you are subject to alternative minimum tax or if your income tax liability was already zero and the additional $100 of income is not enough to bring your tax liability above zero. I'm unable to comment on why state tax liability would not change other than possibly as similar situation where income tax liability was already zero. Check the details of the Form 1040-X and the state equivalent.
