I have an error that is caused by the Case.AccountId field equalling NULL when inside a Before Insert Case Trigger. When viewing the page layout before first saving the record, the account is visibly populated. When logged in as an administrator everything works properly, but when logged in as a custom profile the trigger cannot read the account id. I have checked field level security on the Case object and all profiles have the Visible box checked. Does anyone know any other common reasons why a field would show up as NULL for only certain profiles?

Thanks for any help you can provide.