2021 Crosstrek Limited - Magnetite Gray Metalic
Something similar happened to me a couple times. What I do with the MA1 plugged in and the LED "flashing" green... is to go to the BT settings of the phone and select the BT id of your Head Unit to connect to it. Wait a little while and AA should reestablish a session with the HU. In my case, I believe it happened because at one point I used my wife's phone to test the MA1. Btw, I've been using General Availability (GA) Android 12 and Android Auto 7.4.xxxx betas. I joined the beta program for AA in the Google Play Store. Some of these later AA beta versions have fixes not available in the GA versions. Some of the recent beta releases have addressed issues with text messages notifications.at first the adapter was working great for me, now not so much.
You might also find some help in the Google Android Auto Community
These are some of Android Auto known issues that have been acknowledged by the Android Auto Team as of 02/21/22. I hope that the Spotify music stuttering over BT that I experience when voice navigation goes on is addressed in the next Android 12 Build for the AT&T Samsung Galaxy S21+ mentioned in the Samsung announcement.