When S8 is sending voice navigation instructions to car's BT adapter, a portion of the audio text is skipped (not muted) at the beginning of the transmission. Typically what is skipped is the distance to the next turn or the direction in which to turn. I have reset BT and the network settings to no avail. Samsung support offers the usual list of suggestions, but it's clear that they don't (yet) have a solution. Other Samsung phones, Huawei, Pixel, and other Android models exhibit the same bad behavior. My S8 didn't do this before Android 8, and info collected across the Internet suggests that it may be a combination of Androiid 9 (Pie) and BT 5.0. Currently, my choices are: (1) route audio to speaker and (2) buy an Iphone. I have heard that Iphone doesn't exhibit this behavior. I have a Gear S2 watch which connects via BT. It has no problems, but turning it off doesn't fix the problem. I'm still interested in solutions, but I am not optimistic.
Since I can't use the S8/BT for auto navigation, I thought I'd hook it up to my JBL 2+ smart speaker and listen to music while in the office. After pairing I selected a station and the music started. But as soon as the screen went blank, the music stopped. Perhaps the two problems are related. I'll appreciated any suggestions borne out of experience.