It seems that once you rated your song 1 or more stars - you can’t go back to “zero” stars , One is the mininmum. Anyone on P4+ please check.
Not sure if the P4+ functions the same as the RS1, but on the RS1 which recently got this feature well… you swipe or drag your finger from right (5 star) to left and this should zero out the stars. Give it a try.
I have tried to tap, slide, touch, swipe… I can make more stars, but nothing on the screen will make the 1 star to go away.
I just tried it on the p4+. It works. You really have to “swipe” to the left—so, for example, from 4 stars all the way to the left (the 1st star), and keep going! Then the rating disappears.
issue still persists - even after cleaning the screen and washing hands 
I appriciate your time n effort (nice speakers btw) I will keep trying..
Everything works fine - not sure what happened…