Few understand that the movement of money and information about the movement of money happen on different schedules.
People outside banks often find this surprising.
In ACH, as soon as you get the notification about an inbound credit transfer, it's effectively final. Whether it ultimately settles on the same day or 1-2 days later is irrelevant, since what matters is finality.
ACH credit transfer clawbacks are very rare compared to ACH debit rejections (due to e.g. insufficient funds or fraud).