PGO verticals are failing in sdk's Crossgen.targets

[ViktorHofer]

    D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\targets\Crossgen.targets(153,5): error : Error: Failed to load assembly 'System.Private.CoreLib' [D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\redist-installer.csproj]
    D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\targets\Crossgen.targets(153,5): error : Internal.TypeSystem.TypeSystemException+FileNotFoundException: Failed to load assembly 'System.Private.CoreLib' [D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\redist-installer.csproj]
    D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\targets\Crossgen.targets(153,5): error :    at Internal.TypeSystem.ThrowHelper.ThrowFileNotFoundException(ExceptionStringID, String) + 0x30 [D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\redist-installer.csproj]
    D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\targets\Crossgen.targets(153,5): error :    at ILCompiler.CompilerTypeSystemContext.GetModuleForSimpleName(String, Boolean) + 0x104 [D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\redist-installer.csproj]
    D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\targets\Crossgen.targets(153,5): error :    at ILCompiler.Program.Run() + 0xd77 [D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\redist-installer.csproj]
    D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\targets\Crossgen.targets(153,5): error :    at ILCompiler.Crossgen2RootCommand.<>c__DisplayClass205_0.<.ctor>b__0(ParseResult) + 0x358 [D:\a\_work\1\s\src\sdk\src\Installer\redist-installer\redist-installer.csproj]
        0 Warning(s)
        6 Error(s)

https://dnceng.visualstudio.com/internal/_build/results?buildId=2626577&view=logs&j=472432c3-5b4e-5344-9865-f8b02177131c&t=4e0dc36b-b3ee-5ee5-a81b-3f153830d9b9

For whatever reason, the Windows_Pgo_x64 leg is successful.

@jkoritzinsky @agocke can you please take a look? Any idea why the PGO legs would be missing System.Private.CoreLib?