This is a little hard to describe in words.
I check over my hosted blogs to help find spamming IP ranges. My hits included a post entitled "Developmental Psychology, Natural I/O, and Machine Learning" (hecate.darkglass.net/?p=993)
However, in viewing page titles, a quirk was observed where the engine believes that there exists a page "O, and Machine Learning" as a sub-page of another titled "Developmental Psychology, Natural I".
In other words, it failed to differentiate the forward slash as part of the title from a forward slash indicating a path.
Create a new page with a title field containing a forward slash. Generate a hit and check Piwik reports on page title.
As this is a page title, the division into subpages seems irrational; it should not divide at all as part of page title.
See this ticket: #2956 Actions>Page Titles believes there is a subpage if page <title> includes a forwards slash