I confirm as well. I have latest official play store (not an old or beta version) that now works after applied steps reported before.No! It's works permanently. I have updated GP 7.6.08.N-all [0] [PR] and all works fine (installing/updating apps)
Step-by-step precisely by UPDATED manual (added BOLD necessary steps)
https://xiaomi.eu/community/threads/7-3-30.39428/page-20#post-362878
Old manual have temporary effect.
Sent by Xiaomi Mi5 64GB