Good point with regard to the abbreviation. I know some RFCs explicitly assume "PST" is UTC-8. These RFCs, though deprecated, are still required to be followed in new code (I did this not too long ago).
With regard to the delayed implementation, it sounds like there was an amendment included. The Congressional website doesn't yet reflect this, but in my experience it takes a day or two for the website to be updated (including for the vote itself).
Rubio said, however, that an amendment to the bill would delay its
implementation until November 2023 in order to give the airline and
travel industries, which operate on strict timetables, sufficient leeway
to prepare for the change.