This "Specified filter was invalid" issue was resolved in version 32 of the 8.0 PowerShell module. The version that you're running must be greater than 8.0.306.32 - please verify that you're running an up-to-date version of the module.
My code worked on 7.2.1, but I can't get it to work since upgrading to 8.0. I'm just trying to assign a user to a VDI, Set-QVWComputer is the only command I'm having an issue with.  The error I'm getting is "The specified filter was invalid."  Example command: Set-QVWComputer -Farm (Get-QVWFarm) -PersistentClient 'Domain\UserName' -Identity 'VDIComputerName'               
Can't get Set-QVWComputer -PersistentClient to work with 8.0 PS Module