According to the Google guidelines for breadcrumbs using Schema.org markup the first breadcrumbs trail should NOT be the homepage.
I tried using this markup and using the first trail as the homepage and the results were showing a webpage in SERP like this:
www.example.com > Home > Category > Page
"Home" was actually linked as the first trail.
But I see thousands of other websites using "Home" as the first trail in their breadcrumbs. Am I doing something wrong?