I think that this is what they programmed it as. i.e. title your site or page as how others refer to you (link to you).So, if caribguy has decent number of links using only the brand name as anchor text, then G might have titled it with only the brand name.
Infact some sites I know are now having titles altered with text by which they are linked to by most.This happens when I do a search for the domain name without the extension.
However site: domain.com return the proper on page title for Home page.