IHttpModule behaves differently on different servers

I am developing an application and I am debugging the code with Visual Studio 2013 and Visual Studio 2010 and the code behaves differently with the two programs.

In VS 2010, after the code behind has been executed and the page has been built, execution terminates. In VS 2013, after the page has been built, it receives another call to the context_BeginRequest (Object Sender, EventArgs e) method in the IHttpModule I have implemented.

First problem: why is there this additional challenge?

Second problem: IHttpModule gets the path through GetVirtualPath () and then redirects it. The problem is this: why did the path get the path to the start page and not the page it is currently on?