Thanks for your feedback.
Could you please let me know what car bluetooth system are you using ?
Also other bluetooth devices are working fine for me(i.e. mi band 2)but my car's Blaupunkt Travelpilot NX is no longer able to pair with the phone.
After updating from 6.12.22 to 7.4.27 the Bluetooth connectivity with the car stopped working correctly. Apparently this is a known bug for Android 7.0 and Google has released a fix for this in 7.1.
Any chance we can also expect this fix in our ROM ?