I noticed my CEAC status bounced from “ready” to “administrative processing” overnight, does that usually happen before approval or after an issue?

Yeah that kind of flip happens a lot and it doesn’t always mean there’s a problem, CEAC jumps between “ready” and “administrative processing” when they’re doing internal checks or updating your file, and it can happen right before approval or for completely routine reasons, so the switch by itself isn’t usually a bad sign.