I ran into the same problem. It can be caused by two things actually. 1. The basking spot is not hot enough for him/her to digest the food. 2. He/She is too active afterwards, try not to stress it out while feeding. Just a few months ago my frilled was drinking and i scared her on accident and she threw up the water because she freaked out, Im sure the same could happen with food. Its probably nothing but If the problem persists, get a vet to check it out.