Kha'Zix's Q doesn't refund CD if cast on a non-Isolated target that becomes Isolated during the cast time. It needs to check for Isolation on hit, not on cast. I've had situations where a W would kill jungle creeps or minions but Q would not refund its CD despite dealing Isolated damage + animation.
Post your PBE bug reports here: something not functioning as intended? Store is broken? A champion's ability is not working? etc
Need help? Read our [bug reporting guide](http://community.pbe.leagueoflegends.com/c/bugs/CF5EEDC8FF5AC1A896F517E2C7AE4650C472807F-how-to-report-bugs-on-the-pbe).
Comments about things you don't like or suggestions for improvements go in Feature Feedback.