It seems to me that the AirPods case doesn't "activate" until you open it. Like you can't check their charge without opening the case because while its closed, it's inactive, but when you open it, it starts talking to your phone. I assume since you had the case open right when you got to the bar to put them away your phone recorded their location. But since you didn't use them afterwards iCloud only knew their most recent location as the last place you were when they were opened.
It's so completely dumb if you ask me. I'd rather the case was more aggressive with communicating with your phone and maybe possibly build the AirTag functionality into them so you can find them much easier if someone else happens to pass by them. (If they don't already with the newest versions) I want to know my AirPods battery levels even if they're in my pocket and closed.
Yup, that was it.
It only archives the last location they were actively used. Once they're in the case they're "off" essentially.