ASP.net: Weird web user management issue

This is strange. I am declaring a web user control in an asp.net web page like this

print("<%@ Register Src="~/Controls/blah.ascx" TagName="blahCtrl" TagPrefix="cc" %>");

      

        
        
        
      

    

I have no problem with this until today in the code where it gives me the name blah, no error is declared. does anyone know what is the reason for this?