Why does it keep saying my employer witheld too much Railroad Retirement Tier 1 tax for 2020. They withheld $7667.24 and it says they witheld $7667.24 too much.no sense?

Did you enter this information twice?

Does the W-2 also have a separate line for the RR Retirement Compensation $$ in box 14 too?

Maybe that's what is missing.

I'm having the same issue.  Did not enter it twice, and only entered it in box 14.  Did you resolve this issue?  if so, how?

Click this link for help in How to Enter Form RRB-1099.