Hi,
Thanks for your post :
https://github.com/AlteredAdmin/Dell-PowerScale/blob/main/Warn%20Alert%20-%20Resolved%3A%20Query%20to%20isi_stats_d%20failed.md
I had exactly the same issue today after upgrading from OneFS 9.2 to 9.5.
Since it's not an official Dell KB, I call the Dell support which has confirmed the bug with this new service of stats "isi_pp_d" installed with OneFS 9.5.
They applied the same commands provided in your post but they have also recommanded to disable the service with command below :
isi services -a isi_pp_d disable
I have also request to them to publish an official KB on Dell support site, will see.
BR