I think this was expected. 262K visas were supposed to be allocated in FY2020 and based on that DOS moved the dates in Oct 2020. But USCIS has wasted ~80K to 90K visas , issuing only 180K at the most. Hence, even though FY2021 has potential of 290K visas out of that 80K have already been accounted for in FY2020 demand without getting greened.
But for the wastage of 80K visas last year, we would have seen a very similar surge in PD in the Oct 2021 bulletin.