Alarm Sound when Replacing Stereo Radio Head Unit 2015 CX-9 w/ Bose and Navigation

I've got the 2015 CX-9 with Bose and Navigation but the Head Unit was awful so I'm replacing it with an Android unit. I'm getting the most heinous alarm-like sound so loud out of the speakers you can't stay in the car. The tone goes on for 1 second, off for one second and never ends.

I've double and triple checked the wiring. Not my first replacement.
I've tried another, new, same model, Android unit - same problem.
I put the original radio back in - problem goes away.
I've replaced the Crutchfield harness and PAC (steering wheel controller) and still the problem exists.

The alarm sound starts when the key is turned on and will not shut off until the key is turned off (starting makes no difference). The unit powers up and is operable except NO sound comes through between the Alarm tones. Probably about 120 decibels alternating on and off every second. I've talked to Crutchfield, and the PAC (Steering Wheel Controlled Company) for hours and they cannot find the cause. Does anyone know or have experience with this and can offer help?