You must have indicated you made after tax contributions to the plan. If you did not make after tax contributions, Box 1 and box 2a would be the same. If this is a government pension, look to box 9. The amount of your contributions would be there. If sounds like you have used up all your after tax contributions to offset your benefit amount in 2020 so more of your pension is taxable. My guess is in 2021, all your pension will be taxable.
The pandemic has affected your taxes in many ways. Including reporting in TurboTax the amount of stimulus money you received. Click Here for more information on how the Pandemic affected your 2020 taxes.
