2015 Scion FR-S Release Series 1 with the same issue here. Manual, push button start etc. 8100 and OEM Audio + plug and play amp/dual sub. Had the 8000 prior to this and changed to 8100 for Android Auto. This startup issue is the only real issue I've had with this unit but the randomness is driving me batty as well. If anyone hears of a solution hit me up. I have lost but almost all faith in Pioneers tech support lines based on past experiences.