I am also facing problem in my Moto G5S plus. After connecting bluetooth voice on phone calls are not audible.
But I can listen to songs and video after connecting bluetooth on youtube, gaana, mxplayer.
Problem is with phone calls only.
Same bluetooth headset works perfectly fine on other Android phone (calls, videos, songs everything works very well).
I have installed RR-O-v6.0.0-20180530-sanders-Official.zip
on my moto G5Splus.