I'm not sure I understand your scenario-- is there some reason you're using PowerShell for this task rather than a program written in C# or VB.NET directly? If you build such a program, you can integrate FiddlerCore directly into it and then use the URLMon class in FiddlerCore to set the proxy for just
that application rather than collecting traffic from everything on the system.
I don't know what "Receive-Fiddler" is-- that sounds like a function in some code you've written. Unfortunately, without its source or any notion of how it was written I can't really speculate about what's wrong with that code.
Can you share the code you've written? If you don't want to do so publicly, simply use the "Send Feedback" item in Fiddler's Help menu.
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