Push Notification personalization fails when I use target extension (targetData)

Hi - I'm unable to generate a push notification (iOS) when I use targetData field for the personalization. I see the error message - "Error while compiling script 'content iosMessageContent' line 4: targetData is not defined. SCR-160012 Javascript: error while evaluating script 'content iosMessageContent'". However the targetData field is available in the incoming transition to the push delivery activity. Even in the message window I could access these fields. But if I use any other fields apart from targetData fields (like recipient firstname, lastname etc.) I receive the push notification. Is there any configuration checks need to be done? 

Appreciate a help on this. Thanks!