I have a '16 Toyota that I connect to with Bluetooth. I have problems using the steering wheel buttons and the touchscreen buttons to make or end calls. It seems like there may just be a delay before the hardware responds, so like any other normal person, I press the same button repeatedly. I also had a call drop the connection to the car, but the phone was still connected. I was talking and then the music came back on. The phone was in my pocket, so it took some funbling to get it out, and it was still showing connected to the vehicle.
I also tested in my Ford with Android Auto, and calling seemed to work just fine. I can/will retest using bluetooth in the car just to see.