The error happens when Spotlight references the .Net or OS .dll
It is recommended that the latest .NET version is installed. The Minimum .NET is v4.5. is required for the Performance Health drilldowns and the Spotlight Report Viewer.
1. Run Spotlight as Administrator
2. Try upgrading to .NET v4.6.2
3. Install the Spotlight client on another host, and connect to the same Diagnostic Server to see if it is related to just one machine.