Basically I have this displayed in my Crashlytics report. This error crashes the app. It doesn't show any line of code I written and Google search doesn't help either.
Below are screenshots. Both are showing the same thing just different ways of showing data.
http://postimg.org/image/4k9hb3sbx/
http://postimg.org/image/c2xgd2lqv/
UPDATE:
found that this was related to this bug here NSRangeException on iOS 8