It may be simpler to think of an Hourly Quaddie bet with 81 combinations as 81 separate straight multi bets.
In the event of a voided outcome, PointsBet’s existing Straight Multi terms and conditions (3.12.5) will apply to each individual combination in the Hourly Quaddie bet.
If one of your selected runners is scratched or a race is canceled, the affected selection will be disregarded, and your bet will continue with the remaining legs. Your bet is still alive, and as long as your other selections win, you will receive a payout based on the winning selections. As your bet is still alive, if you do not have winning outcomes in remaining legs your bet will be settled as a loss.
If all selections within a combination are scratched or the entire race is abandoned, the stake for that specific combination (stake per combo) will be refunded to you.