@RebeccaLChin
It does not affect your 2021 tax liability. On your 2020 tax return you got a deduction for half of the full amount of self-employment tax, even if you deferred paying part of it. The deduction was calculated on the full amount before the deferral.
On your 2020 tax return the full amount of self-employment tax, before the deferral, is on Schedule SE line 12 and Schedule 2 line 4. The deduction for half of that amount is on Schedule SE line 13 and Schedule line 14. The amount that you deferred is on Schedule 3 line 12e.
