This is another problem that does not yet have an Apple-supplied solution.
Posts on the Apple support forums show problems with the Bluetooth on the iPhones which won’t ensure proper connectivity with devices to the other Bluetooth Devices.
According to the posts, the issues majorly relate to connecting their iPhone XS or iPhone XS Max to their vehicle’s infotainment system, but it also weirdly affects some other Bluetooth-equipped devices.
The issue doesn’t seem to be with the Cars
It’s not limited to a specific car manufacturer, as vehicles by Kia, Audi, Subaru, and Mercedes all appear in references to the head unit connectivity failures.
Measures taken by users to fix the issue included removing the pairing from the car stereo and the iPhone before re-pairing once again, but this is only a short-term solution before the connection fails again.
One of the users mentions they contacted Apple Support, who suggested to check whether the car had the latest firmware update for the unit, but apparently it had no update was available.
Some users believe it is a problem that could be solved via an update to iOS 12, pointing towards previous similar compatibility issues between iPhones and entertainment systems shortly after new iOS releases.
What Apple has to say till they find an answer to the issue?
Regardless of the root cause of the issue, affected users may wish to check with their vehicle or after-market unit vendor for any updates to their hardware, while waiting for a response to the problem from Apple.