Well d'oh. The 27th is the day she gets her comfortis every month, which she absolutely loves. So I gave her the comfortis, then I gave her a pretty good amount of green beans for a snack; a lot more than I usually do, since it's her birthday after all. I guess that wasn't a good idea to give so much food after the comfortis, as she just puked the green beans up whole!
Then when I smelled her puked up green beans I wondered why they smelled like comfortis. Ah what a brain fart, giving so much food right after her medicine. She has never puked the comfortis before, so I think it was just the overfeeding right after. But now I gotta call my vet tomorrow to make sure she should get another dose of it for the month (his office is closed on Thursdays).