Up until about a month or so ago, if I @mentioned a task in a Doc, that Doc would appear under "References" (I think it used to be called "Backlinks"?) in the task view for that task. I noticed that this feature stopped working about a month ago. However, @mentions of tasks in Docs that I created back in June are still appearing properly as a Reference Relationship for that task... it's just that I can't seem to make that happen anymore.