It says like this

Update 8/15: Rated M stories are now separate from non-Rated M stories. Please check the Rated sections for your favorite Rated M stories. Stories that fall under tags that are considered Rated M will automatically be marked as such until the tag is removed. A list of Rated M tags can be found in the Browse topics section.

I unmark the M and click save change. But the mark comes again automatically?????

WTF is this?

I contacted AFF few days ago that I want to remove the M. cos nothing on my fic. Still no answer. And I think that update on homepage is to answer my question. But I still can not do it... TT_TT