Uploading file in MVC under Debug forces program to exit

Question

So, I create new empty/MVC project, add simple controller and view for uploading file, lauch program under the Debug mode and trying to upload file. After selecting file (immediately, right after chosing the file in explorer!) program exits debugging and I'm getting 404 in my browser.

 

When lauching project without debugging everything works good, but this is not a solution... what if I need to test uploading exactly in the Debug mode?

 

In ASP Core I'm getting the same issue.

 

I've tried different variations of code, including version of A. Freeman, published in his book "Pro ASP.Net MVC 5" - nothing works.