Isn’t Google supposed to adhere to the canonical tag?

google-logoLast month Google announced they would be supporting the canonical tag across cross domain platforms. The canonical tag has been supported since February for both internal URLs and subdomains. However, today I noticed that Google was returning a subdomain and a root domain with the same content, even though the subdomain has a canonical tag pointing to the content on the main domain.

IMDB is one of the most popular film websites on the Internet and provides movie lovers with in depth information and reviews on Movies and TV Shows. I have been really looking forward to season 6 of Lost on Sky1 and was searching for the popular US TV show – when I came across the following:

Lost canonical issue IMDB

Lost canonical issue IMDB

Below is the canonical tag that features in the </head> element of the subdomain:

<link rel="canonical" href="" />

So what gives? Isn’t Google supposed to be returning the canonical page as highlighted correctly by IMDB?