WebResource.axd only shows 1 ver in Sources Quantum 61.0.1

Trying to debug some code in my ASP.Net application - we have a .axd which injects javascript files into the page it utilises querystrings to ensure different files. In the debugging tools you only see one instance of my WebResource.axd in the sources (Debugger) so you cant debug any of these other instances.

Is this a bug or is there a setting to turn this feature on? Not sure if this is the correct platform to report this?