The UWP app I'm working on suddenly throws these errors. However, even with these errors project builds successfully. I just need to know what happens here.
I found the solution to my case. I had several projects in my solution and all of them were using
Microsoft.NETCore.UniversalWindowsPlatform V 5.2.3
except for one project. It was using
Microsoft.NETCore.UniversalWindowsPlatform V 5.0.0
When I update the 5.0.0 to 5.2.3 all the errors went away.