Because there has been a temporary policy in place for cruises from spring 2020 thru Nov. 2021. (and that has adjusted during the past year as the pandemic continued)
Prior to that, I believe there was a change in PIF policy sometime in maybe winter/early spring 2019. That is the "standard policy" under which your 2022 cruise now falls. I believe it's 120 days out for cruises of 7+ nights.
Prior to that was a PIF policy change in maybe 2017 (?) that was very convoluted based on length of cruise, embark/debark port(s), time of year, etc.
So...depending on when you booked and/or made changes to your reservation, there have been changes.
To my knowledge online check-in has remained consistent, other than you have to be PIF to book onboard activities (Palo, port excursions, etc.). That is 75 days for new cruisers, 90 days for silver, 105 days for gold and 120 days for platinum. But official PIF may or may not correspond to the online check-in date, and that has been true for a decade or more.