Seizures after vomiting

Seeking advice or looking for similar cases.

My dog, a 2,5 year old FT Cocker Spaniel has been experiencing seizures occasionally for the past year. A seizure always starts with him throwing up and it only happens on an empty stomach (if he throws up his food, nothing happens). He will throw up bile and shortly after get a grand mal seizure. If we manage to give him some food right after the throw up, nothing happens. Has anyone ever experienced this? So far the vet haven’t been able to find the cause.