Very Slow Advisor - Plesk Update time out

In recent days we've come across a new issue involving painfully slow Plesk Advisor, and an inability to use the Plesk Update function. We have found the trigger for this behaviour, which doesn't appear to be documented yet by Plesk.

This is on Plesk Onyx 17.8 update 38 on dedicated servers in OVH data centres

We looked at this article:
Plesk Installer and Advisor...

Very Slow Advisor - Plesk Update time out