Delayed 2020 Unemployment payment received in 2021. Will I be taxed for this delayed payment?

I applied for unemployment in May 2020 and turned in all verification requested. I wrote DETR letters, emails and faxed them asking when my claim would be reviewed for a decision. I finally received a decision and payment for 2020 in January or February of 2021. In 2020 $10,200 of the unemployment insurance payment was to be exempt from being taxed. I received over $12,000 in 2021 but it was all based on May to September 2020. Will I now be taxed on that full amount of $12,000 because DETR did not pay this to me until 2021? Or is there an exception because of the delay in payment that was not my fault? Thank you.