Board Thread:FAQs/@comment-29313623-20180812234833/@comment-4010415-20180812235859

It seems that not all Maidens are weak against Silver Eyes, and Cinder was just a special case.

If all Maidens were affected, then Raven would've been hurt when Ruby used her Silver Eye powers during the Battle of Haven. Her Silver Eye blast isn't limited to her field of vision, considering that the Dragon in Volume 3 wasn't in her view but was turned to stone anyway, so just because Raven was out of her view, that does not mean she would be safe.

We watched Ruby's Silver Eye blast fill up the room, and Raven was perfectly fine. If she had been affected, then the writers would've had to show that because Qrow would've reacted to it, knowing that it means she's a Maiden. But that didn't happen. Because she wasn't affected.

Qrow stated that the Silver Eyes have an effect on Grimm, so the simplest explanation with the fewest assumptions is that Cinder was affected because she used Grimm - a magic glove containing a Grimm beetle that was absorbed into her and a Grimm arm.