While the connection hangs there is no connection with the car in the log, not even a connection attempt. There are lots of unknown HCI commands, but I'm not sure if this is the root of the problem. This may be a low level Bluetooth problem on your phone.
I don't know what you can do about it. If there is no firmware update which fixes it you may think of automatically switching off/on Bluetooth with a tool by some clever trigger, e.g. same time every day. The "Tasker" app can do this, maybe others, too.