That's the same justification I've heard, at least for early morning stores. Overnight stores are told to acknowledge as soon as possible (before midnight) to help with priorities.
Honestly, corporate just needs to add a delay to when product counts are updated for online orders after trucks are acknowledged. Back when COVID first happened, my store had a lot of issues because we'd get dozens of orders the second we acknowledged the truck (along with the issue of having guests grab items that were ordered between when they initially dropped and when they were picked, but that's another issue entirely). That meant we'd either have to set batches aside until the truck was finished or (for new/uncaring TMs) things we just received were being INF'd because they were still deep in the truck. This is clearly a consistent problem for a lot of stores, so it's strange that corporate isn't doing anything to fix it. Delaying counts isn't going to affect sales either way, so it's such an easy issue to address. The same goes for updating counts only when RTS is worked rather than when it drops in.