This fixlet is showing applicable on over 8000 of our Windows 10 1809 workstations. When we attempted to pilot it to 8 pilot machines all 8 failed this update. Every machine showed an error in the setup log that stated the update is not applicable to the machine.

Fixlet ID 450699001 - KB4506990 for Windows 10 (x64) 1809 appears to have incorrect relevance

bma July 10, 2019, 11:20pm 4

An updated fixlet was released in Patches for Windows version 3333 which hopefully helps.