When she regurgitated the first time how did you treat it? Did you wait several weeks for her stomach to settle and then offer a smaller than normal feeder, or did you keep her on the same feeding schedule? Did you dust her feeder with a probiotic such as NutriBAC to help re-establish her gut flora?

When you said the vet found nothing wrong, what did he test for? Did he do a fecal exam for parasites and PCR for cryptosporidia?

What is your quarantine process when new snakes arrive?