I think you were lucky, and I certainly wouldn't advise the OP to rely on this. There are too many documented instances here where proper credit wasn't given when checking out before midnight or checking in after midnight. It's usually possible to sort this out after the stay, but why would the OP put himself in that position ? Just check out using the app the next morning.
yes, i am aware of those reports. since I no longer really require the night credits I thought I'd give it a try. maybe this "bug" in HYATT IT is now fixed?
but agree, not worth for the OP to risk it.