The default display of related child, sibling and parent articles has changed for the 1.10.6 templates release.
All related articles were shown below the article and a #breakout or #railstory keyword tag was required to pull them into the article rail.
Child and parent articles are now shown in the rail with a breakout style treatment by default.
Articles are grouped in a single box by default. Child articles tagged #breakout or #railstory are displayed in their own box.
Individual articles can be changed to a headline-only style by adding #breakoutheadlineonly, or hidden altogether with #norail.
This change only affects articles, other assets will continue to show parent articles below the content by default.