I have today found out a major bug in Microsoft Windows Virtual Desktop (WVD) with OS Windows 10 Multisession version 2004. After helping a client with expanding some FSlogix storage, I saw there was some important patches for OS (CU) and some security patches, its always recommended to apply these patches, as you will gain performance and stability and improve security.
But after applying these CU, I ran into a very strange problem that when you login to the Multisession host from any WVD client, the Windows screen flicker and keep updating in the GUI and you couldn’t do anything not click anything inside the desktop. After some research on the web, I saw other people facing the same issue with as I saw. The interesting part was that Pieter Wigleven from Microsoft, confirm this bug and that the Microsoft Search team will solve this part in future builds of Windows.
UPDATE 22TH SEPTEMBER 2020 FROM PIETER WIGLEVEN, MICROSOFT This specific issue only impacts Windows 10 Enterprise/multi-session version 2004 and the fix is currently scheduled for release in the third week of October 2020. In that third week of October - if you manually click the “Check for Updates” button you will get it. If you won't check manually, you’ll receive this bugfix in November's Patch Tuesday (second week of the month).