That's a good point. At the year end we were still in the FA Cup and CL, and still could have theoretically won the league (albeit that was unlikely). So it's entirely possible that we paid, or at least provided for, bonuses for progressing in or even winning those competitions.
The accounts were signed in March 2021 so the liabilities would have been reviewed at closer to that date. They would not have taken into account bonuses for competitions that we now know we didn't win.
I'm repeating myself from earlier posts but from Page 33 of the Financial Report (see below) it looks like they DID take into account player bonuses based on an assessment of probable player bonuses as at the year end 30th June. This surely has to partially account for the increase in wages particularly if it was an optimistic view relating to Champions League progression.
PLAYER BONUSES
Delays to the completion of the 2019-20 Premier League season, UEFA Champions League
and domestic cup competitions due to COVID-19 meant that an assessment was made,
on a player by player basis, as to whether it was probable that individual player bonuses
would be due and therefore should be accrued in the financial year. All information available
to management on 30 June 2020 was considered when making this assessment.