Hi there and thanks for your question. It is good to hear that Tippy is eating well and bright and alert. This makes me think that this is not anything too serious.
It sounds like the vomiting does not happen too frequently. Unfortunately some cats will just vomit and we do not know why. I remember back in school we had a professor who said, "If you ever meet a cat who doesn't vomit, check it out cause there's something wrong with it!".
It is possible that the vomiting is due to hairballs even if there is no actual hairball coming up. Sometimes they can sit in the stomach and occasionally block the outflow to the stomach into the intestines. Most of the over the counter hairball remedies work well. You can give about an inch of the malt 2-3 x per week to see if this helps.
If the vomiting is becoming more frequent some other possibilities include a foreign object in her stomach, an allergy to her food or possibly inflammatory bowel disease. Most cats with IBD have diarrhea, but some will just vomit. So, if this is happening very regularly, or if she is not feeling well then another vet checkup is probably a good idea.
Also, if you have changed her food recently or added a new type of treat this could contribute to some stomach upset.
I hope this information helps! If you have more questions regarding this problem, just hit reply. Or, if my answer is sufficient, then please hit accept. Thanks!