User blog comment:Zathronas/Analysis by an author: Volume 2 episode 12: Breach/@comment-11188061-20141031021539/@comment-11188061-20141031053946

"A cliffhanger or cliffhanger ending is a plot device in fiction which features a main character in a precarious or difficult dilemma, or confronted with a shocking revelation at the end of an episode of serialized fiction."

Is Yang faced with a precarious or difficult dilemma? Definitely not precarious, and not really a difficult dilemma. We don't even know what the hell is the real issue; it wasn't entirely clear. Is there a shocking revelation? Could've been, except that again, no literal reveal that OH-MY-GAWD SHE'S YANG'S MUM! and her identity, although confirmed to be related with Yang because of their resemblance, is still a mystery.

So cliffhanger? You can argue that it is, but I can argue that it isn't either. In my opinion it's not, because that could easily be interpreted as The End of the RWBY anime if RT wanted, since it leaves no clear or urgent question marks that needs resolution.