Object Id conflicts with field of parent object

when the title of a content converts to an id that equals a field of the parent object

How to reproduce it

  1. Add a Field named "xyz" to a folderish content type (e.g. to Folder)
  2. Create a Folder (which has a field "xyz")
  3. Add content into folder with title "xyz"
  4. Save the new content

Following screen shows

Where should this issue be filed?