No, it usually happens after one meal a day or every other day. It's always either her lunch or dinner that she vomits and it happens usually about 2 hours after eating. Most of the time it's undigested food, but it's definitely vomiting and not regurgitation.
Besides the vomiting she it totally normal. Her bowel movement are normal, she poops roughly 2-3 times a day and it's a good texture (not diarrhea or constipated) and color.
It is possible that she could have a partial blockage but the vet didn't seem to think that was the case since she's having normal bowel movements, not in any pain, and have clear x-rays.
I hope we find out whats wrong soon too! Yesterday we met with someone who specializes in canine diets and we realized most of the food we give her have been bird based (chicken, turkey, duck, etc.) so her recommendation was to do a trial of a lamb based food before going for the expensive tests. We're keeping our fingers crossed that this works!