Errors showing up after Radzen Blazor Studio update

The errors below appeared immediately after I upgraded studio and they were not shown before. I have never touched these files so I am baffled how they could suddenly have errors. Mainlayout.razor exists and has no errors (at least none that show up in output). Here they are:
C:\Development\Projects\ET Blazor\ET\ET\Components\Pages\Error.razor(3,13): error CS0246: The type or namespace name 'AuthorizeAttribute' could not be found (are you missing a using directive or an assembly reference?)
C:\Development\Projects\ET Blazor\ET\ET\Components\Pages\Error.razor(3,13): error CS0246: The type or namespace name 'Authorize' could not be found (are you missing a using directive or an assembly reference?)
C:\Development\Projects\ET Blazor\ET\ET\Components\Routes.razor(4,75): error CS0246: The type or namespace name 'MainLayout' could not be found (are you missing a using directive or an assembly reference?)
Microsoft.NET.Sdk.Razor.SourceGenerators\Microsoft.NET.Sdk.Razor.SourceGenerators.RazorSourceGenerator\Components_Routes_razor.g.cs(127,168): error CS1662: Cannot convert lambda expression to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type
C:\Development\Projects\ET Blazor\ET\ET\Components\Routes.razor(13,37): error CS0246: The type or namespace name 'MainLayout' could not be found (are you missing a using directive or an assembly reference?)

This type is part of Microsoft.AspNetCore.Authorization, check if you have it in your project references:

That didn't fix anything, as I suspected. However, it did cause a reaction. Not only do the old errors remain, there are now a bunch of new ones. I still wonder why the old version of your studio didn't show these errors.

I’ve never seen such errors reported before. If you have active subscription you can contact us at info@radzen.com with details how to reproduce these errors.

If you mean to your studio, then I don't. It was all I could do to convince my employer to let me install it. They weren't going to license it since they have standardized on Microsoft's VS. Since adding that include statement made a difference, I will continue to look for others that I might need to add.

I figured out most of the errors but the one for MainLayout is still there. I've run out of guesses at what using statement might be missing. There is one other that has me stumped:
C:\Development\Projects\ET Blazor\ET\ET\Microsoft.NET.Sdk.Razor.SourceGenerators\Microsoft.NET.Sdk.Razor.SourceGenerators.RazorSourceGenerator\Components_Routes_razor.g.cs(141,168): error CS1662: Cannot convert lambda expression to intended delegate type because some of the return types in the block are not implicitly convertible to the delegate return type [C:\Development\Projects\ET Blazor\ET\ET\ET.csproj]
For one thing, the file referenced in the error does not exist anywhere on my laptop so I have no idea what reference might be missing.

This file is the transformed razor to C# during the compilation - the original file is Routes.razor.