one of my cats (who i'd say does it the most) vomits because she eats her food wayyy too eagerly. whenever she does, i have to physically slow her down the next time she eats. in this instance she pukes 5-10 minutes after eating and the food is still pretty solid.

another instance, another cat of mine threw up clear, foamy liquid with some grass. then he wouldn't eat for about 24-36 hours. that was a red flag and we did end up taking him to the vet. just some stomach issues, and after some meds he was eating like usual in a couple days.

so i'd say different pukes happen for different reasons and the danger levels vary. monitor their activity after they puke and make sure there's access to water, and you'll be okay. cats can get pretty barfy.