No.No! It's works permanently. I have updated GP 7.6.08.N-all  [PR] and all works fine (installing/updating apps)
Step-by-step precisely by UPDATED manual (added BOLD necessary steps)
Old manual have temporary effect.
My Mi5 either with Global or with Xiaomi.EU have the issue, rooted or not it doesn't change.Ok in global oficial from xiaomi no google playtore problem, confirmed in my brother Mi5.
Since then I have got back that issue, so not worth to try.
I tried yesterday but didn't help...Just noticed an update for playstore on xda labs Version 7.7.08
Also available on apkmirror
Release yesterday, so has anyone with problems with the store tried the new version?
I have to say you are fully right!!!Imo there are two kinds of people:
1. Those who have already got Waiting for WiFi Google play store bug
2. Those who will get Waiting for WiFi Google play store bug