{{ parent }} not working unless I use {{ %parent }}

[RyanRoberts]

I have two collections, one for news articles and another for services. Both mount to their respective page in a pages collection (News and Services). Currently the news articles use {{ parent:title }} and {{ parent:url }} in their header to display a link back to the root News page. Great. However, this doesn't appear to work at all for the service pages, {{ parent }} simply produces nothing. I found this issue which lead me to try {{ %parent }} and that works!

But now I'm unsure what would cause that situation or what I've done to need % in front of the tag.

[RyanRoberts]

Argh, the sidebar parent field snuck back in! That's the issue.