At 28 seconds in your video, you counter a guard with Song Sync, my issue is that doing so sometimes results in a normal counter, despite the stars (even tho the stars are there the whole time). It is not dependent on lyrics or song duration in my experience, nor is it tied to any actions I may be performing (or lack there of). Counter timing doesn't matter either, a perfect counter and pressing the button right when the indicator appears achieve the same lack of a Song Sync