User blog comment:DaNASCAT/Technical Update: November 26, 2013/@comment-188432-20131127222615/@comment-13301-20131127223227

The default behavior of the standard MediaWiki installation is to include H1 in the TOC. Wikia introduced this bug when they changed the way TOC was rendered.

I also agree that H1 shouldn't be used in articles. But that doesn't make Wikia's change to TOC to be conform to MediaWiki behavior. On the other hand, I don't see how it helped in enforcing local rules