PAX isn't related to the number of tickets sold, it's the number of tickets issued.
Rarely are PAX and announced numbers aligned, but as
@SLRBRONCOS mentioned previously, it is an indicator for the type of crowd a match may draw, but like all indicators, shouldn't be taken in isolation.
For a number of clubs, like Broncos & Rabbitohs, the PAX will always be lower than the potential crowd for the game. This is because members are allocated seats separately to ticket sales (both clubs use Ticketmaster for membership & play at Ticketek venues) and they play at venues which have Stadium members.
For some clubs, memberships are included in the PAX, so the PAX number instantly starts higher than the crowd that will be, considering the average attendance for ticketed members across NRL clubs is under 50%.
You then have give-aways which can throw it out massively.
For the Bulldogs today, Illuvium, the match day partner (and reason the Bulldogs were wearing special jerseys) were giving away tickets to their own customers. You then had the Development Officers in the Canterbury-Bankstown region also giving out tickets this week (which is pretty common for last game of the round) to a number of schools.
Now generally when you're doing give-aways you pre order the tickets and do it in bulk, because both Ticketmaster & Ticketek charge a fee per ticket issued.
It's often cheaper to pre-order thousands than print hundreds, the problem is then the PAX suddenly increases dramatically even if the tickets aren't used.
I can't say exactly why Accor may have had PAX in the 30,000's today, but if I'd guess, I'd imagine you have a combo a members, sales & freebies there.
Looking at most of the talk for the game, what was shown on the Ticketek website, etc, the announced crowd fell with the range most people were predicting.