Board Thread:FAQs/@comment-35965952-20180623155453/@comment-4010415-20180623204322

I think it's possible that the Grimm beetle was inside of Cinder, so Ruby's Silver Eye powers were able to detect the Grimm beetle within Cinder. Either her eyes considered Cinder part Grimm because of the beetle, or the beetle panicked and caused a lot of damage to Cinder while trying to escape from the Silver Eye powers.

It seemed like Cinder still had full use of the Fall Maiden powers, especially considering that massive blast that she sent toward Ozpin.