deadsea - 3:11 pm on Jan 21, 2013 (gmt 0)
Yes, it could be one of the reasons. For both pagerank and anchor text purposes, Google treats page.html and page.html#anchor as separate urls.
This appears to be because the support linking into sections of documents. We've seen this in the SERPs for wikipedia, for example. On the other hand, it seems like an algorithm weakness that can still be exploited by technical SEO, and may in some cases like this cause unintended consequences.