It could be some bug, maybe you just need to update Google Maps.

 

Unlikely Google Maps, the phone application uses the Bluetooth services provided by smartphone OS and hardware "as-is". Apart of signal/interference, Bluetooth is tricky by itself, it has many standards and modes, the one for the calls is mono and uses speech quality, and when music goes it must be stereo HQ. Smartphone has several modes to choose from, depend on the use, and so does the car. Noone but Google knows if Maps uses phone or music mode to speak the directions.
And, unless your phone and it's OS version is exactly as recommended by car manufacturer, it is an uncharted territory, nobody bothers to test all combinations, it drives development costs high and affects immediate bottom line, you know ;-)
There are not too many options to replace/fix in-car BT, so your best bet is to find a combination of device and settings that works by way of trial and error. Try with a different phone or tablet/computer and see what's different. See if you can pair two phones with the car, one for talks another for media (there is a choice in car BT settings, at least in my 2015 Touring), and use GMaps on either, maybe you can figure out the right combination that way. You may be better off connecting phone to car audio by cable or getting an aftermarket car dongle (BT to car audio cable/FM).

 

Encountering the same issue!! Let me know if you find out a solution

 

I had this problem on my 2014 CR-V when I had a Samsung Galaxy s5 it would stream then disconnect on it's own, currently don't have this issue as much no more when I changed to a s7 a year and a half ago, it happens but not as bad as before , this never happens on my Toyota, I suspect it's the Honda unit.