Hi. I've experienced the same thing. A stop on the journey can be a bit of a nightmare. Sometimes navigation resumes from Android Auto but often the phone is needed. Sometimes I find even then that the pointer and map on the Chigee (in my case) don't update at all and remains static. I then pull over again, go back to my phone and start navigation and the phone screen goes solid grey and the app locks completely. It's a total lottery.
I think some more work on Android Auto is imminent. I trust it will get there, but for now I bought Sygic for use with Android Auto. MRA was just hanging too often, and I was having to pull over too frequently to get my phone out.