When searching for a flight on 9/20/2022 I see there is a flight at 00:50 at the bottom of the departures while all the other flights are in chronological order... this is very confusing as I initially thought this was a flight leaving 12:50am 9/21/2022 but based on what I'm reading posted on ANA's website, a 00:50 flight on 9/20/2022 literally means you have to check in on 9/19/2022...

Per ANA's website:

To passengers with a reservation for a flight departing after midnight

Thank you very much for flying with ANA.

For late-night flight*1 reservations, we have seen passengers reserving their flight for the wrong date as well as passengers arriving at the airport one day late.
Airport check-in procedures will begin one day prior to the departure date for flights departing after midnight.

• *1."late-night flight" are defined as flights that depart between 12:00 AM and 1:59 AM.

Example

Flight NH203 departs from Haneda at 00:55 on April 1, so check-in takes place on March 31.
However, some passengers mistakenly come to the airport on the evening of April 1.