Hey @BrianAppleyard1 ,
that is odd. Can you try these steps to try to get this sorted?
1. Perform a Soft Reset on your phone by pressing and holding the Power, Bixby, and Volume down buttons for 10 seconds and if a warning pops up, press the Volume down button.
2. If the issue persists after that, try to unpair and pair back the device after 5 minutes, If this doesn't work, clear the Bluetooth cache and data by heading into Settings> Apps> 3 dots (top right)> Show System Apps> Bluetooth / Bluetooth Share / Bluetooth Test> Storage> Clear cache and then Clear data.
3. If none of these steps make any difference, speak with your car sound system manufacturer who will be able to check whether the Bluetooth system in the car is compatible or whether it needs updating.