Why is Apple Music not auto-playing where it left off?

[sciteach]

IOS 11.2.6 IPhone 8 - I never know what my phone will do when I get into my car.

If I were listening to a podcast with Overcast when I got out of the car, sometimes Apple Music will auto-play when I get in the car again.

I could be listening to a radio station on Apple Music last and it will auto-play a Playlist next time I get into the car.

How do I get iOS to auto-play to what I was last listening.

Thanks!