Thank you once more for your offer to help me getting this update to work!
In the KB description it is stated:
This update enables the Diagnostics Tracking Service in Windows 8.1 and Windows Server 2012 R2. This tracking service collects data about functional issues in Windows components.
It seems to me that the update installs some telemetry function, which could explain why you find corrupted telemetry-related files.
Before I started this topic I spent the best part of a day in hunting down this update as the culprit for the sfc error I showed in my opening post.
I think I can live without the telemetry function, so I am not very keen to spend more time on this.
I'd rather wait for Microsoft to address this.