Re: Bugs and Defects
The bluetooth problem reported in various places for the earlier versions of Windows 8.1 is still there. I am experiencing it with Windows Phone 8.1 with update 1, on the new HTC One M8.
If you stream music to your car over bluetooth, you can't, at the same time, use Cortana's voice interface. When you touch the voice input button, the music is silenced as intended, but Cortana still doesn't understand. The checkbox that was provided in bluetooth advanced settings actually makes the problem worse.
Also, when streaming music over bluetooth, the Here Drive+ navigation app works unreliably. The music is silenced when the nav app wants to talk, as intended, but the bluetooth channel or the CPU are still clogged up so the phone isn't able to speak a complete sentence, and reacts slowly to changes in speed or direction. Some users are reporting that the nav app doesn't speak at all. The bluetooth advanced setting for voice input makes the nav app pretty much inoperable for many users.
The Microsoft support site has quite a few complaints about this on several devices, but the replies from Microsoft reps seem to be dismissive of the problem, which usually means they don't know how to fix it or they don't think it is important.
This problem seems to have started with Windows Phone 8.1. I was able to play music and use Here Drive over bluetooth at the same time just fine with my HTC 8X with Windows Phone 8.0.