My pug has a slight underbite but we thought this was normal and have no concerns. However, we just made a claim to Petplan about an eye injury that was paid no problem and we have received a letter that says the vet has noted the underbite and this is now a pre existing condition that won't be covered. Also as he had a check of anal glands they won't cover any further issues. He's only two! Isn't an underbite normal??