Why am I now getting errors about not finding redirection.config?

Question

I maintain an ASP.NET app written years ago by someone else who left before I came to work here. He wrote the app using .NET Framework 2.0. It has been on that version ever since. When I first started maintaining it, I used Visual Studio 2015. Then as time went by, I've used VS 2017, 2019, and now 2022. It is important to note that I have used VS 2022 fine, until today. I have to add some new functionality to this old app. So, I created a new branch, checked out the new branch, got into VS 2022, cleaned the solution, and then rebuilt the app. All tasks I've done hundreds of times before. But today, for the first time ever I got this error message:

Also, the project is no longer visible to VS 2022. This is what it looks like in VS 2022's Solution Explorer:

As you can see by the above image, the TimeTrackSite project has a status of "load failed". Something it's never had before. FWIW, if I look at the folder structure of Timetrack solution I can find the TimeTrackSite fine. It's only VS 2022 which cannot "see" it. Why am I getting this now, when I've never gotten this error before? I don't know if this is a coincidence or a part of the problem, but I did apply an update to VS 2022 today before I created the new branch. It is now at version 17.8.6. If this is the cause of my problems, then I'll gladly uninstall 17.8.6, so I can do my job. But if it is something else, please give me some guidance!