Retirement tax questions

Hi.  My pension distribution (loan offset) in 2020 was $9,831.  In doing 2021 return I went back to 2020 for review and saw that the NYS income adjustment to Federal for the pension exclusion was only $4,096.  I can't figure out how this number was calculated.  It seems it should be the whole amount of $9.831 which is below the maximum $20k exception for single. 

I saw some notes that said there was a glitch and you should go back and update TT and then go through 1099 R entries again.  My return was filed but I created a duplicate copy to see if I could do that and if it would change.  But it did not.  

Can you help please? Diana