Users who turned to Google’s forums to report the problem claim that even if they manually revert to the radio after running Android Auto, the switch to media apps automatically occurs either immediately or after a few minutes.
“Same issue started happening to me, VW Golf GTI. Head unit radio only works if the phone (Pixel 3) is unlocked or disconnected from the car, obviously completely defeating the purpose of Android Auto,” one user posted earlier this week.
At the time of writing, no workaround is known to exist, though some users claim they managed to restore the radio by keeping their smartphones unlocked. That's obviously not very convenient, especially during long drives.
Also, it’s not known if downgrading to a previous version of Android Auto resolves the problem; on the other hand, installing the latest updates doesn’t seem to produce any improvement. Users have reported this behavior with various mobile devices, such as the Google Pixel and Samsung phones, as well as in a wide variety of car models, including from Nissan, Volkswagen, Honda, Hyundai, and others.
The good news is that Google is already investigating the whole thing, though for now, there’s no ETA as to when the company could come up with a fix.
A Google community specialist said the reports have already been forwarded to the Android Auto team, who is monitoring the available information to conduct a thorough investigation of the bug. More details on what’s happening will only be shared at a later time.