The issue presents itself when a Global Template is created with the "Page Tree" and/or "Page Tree Search" macros and template variables.

Steps to reproduce

1. Create a new Global Template with the offending macro(s)
2. Use this global template to create a page
3. Advance past the variable fill in page (you can leave the vars blank or fill them in, it makes no difference)
4. You will notice that the breadcrumb bar now reads "Undefined Space" (I attempted to manually modify the location of the page with the location button at the bottom of the edit page to no effect)
5. Hit Save page
6. Upon saving this newly created page the "Page Not Found" error is displayed and the page is not saved