I check the Form Social Security Benefits worksheet and found I had a supporting details entry for Box 5 of Line A. I had listed the 2 different payment amounts from sums on the details. I removed the supporting details sheet and went back to the Step by Step and the interview process went forward as normal.
This solution has worked for me but may not for you. Check if you have a supporting details sheet for Box 5 on Line A and try removing it to see if Step by Step starts working for you.
SJHE
