Gotta be careful at those moments. Some banks and credit unions "forget" that there's a bill pending RIGHT before they deduct it permanently. It happens right when they swap a deduction from "pending" to final. Can up to an hour lag (or more) before they do it too.
I learned the hard way, but back then, my credit union was nice and didn't charge overdraft fees for the first overdraft in a day. Now they've basically changed all their rules to basically being the same as a regular scuzzy bank, but they don't have the perks, benefits, or number of locations as a scuzzy bank, so I'm thinking of just dropping them.