Include recursion detection isn't working as expected

Steps to reproduce:

1. Create a document "Sheet" with content 

   Sheet
   
   {{velocity}}{{html}}$tdoc.getRenderedContent($tdoc.content, $tdoc.syntax.toIdString()){{/html}}{{/velocity}} 

2. Create a document "Page" with content

   Content Page
   
   {{include document="Sheet.WebHome"/}}

Expected result:

When displaying "Page", the content stops at some point, probably after "Content Page Sheet Content Page" as the include macro detects recursion.

Actual result:

The content is quite long with repetitions of "Content Page" and "Sheet", ending in a error that says "java.lang.StackOverflowError".