If my above assumptions are correct, then maybe it might be better to place the launchreview call elsewhere in your app instead of when it first launches - because if google does pop-up a rating dialog, it may interfere with some other view/object that's initializing in that activity and cause an asynchronous conflict between your apps UI and the possible google ratings dialog.
This way you can then pick a spot to place the launchreview in your app that would be the most appropriate time to display the ratings dialog and one that you are sure wont interfere with any other UI of your app (and a spot that would make your app's logic easily work with the InAppReview_OnComplete event).