IIS redirect inserting double forward slash

Question

Can't seem to work out why the following is resulting in a double slash being added:

<rule name="GenericRemoveDotASPX" stopProcessing="true">
    <match url="(.*).aspx(.*)" />
    <action type="Redirect" url="{R:1}{R:2}" appendQueryString="true" redirectType="Permanent"  />
</rule>

Using the above rule if I enter (the first part is {R:1} www.blah.com/blah and the 2nd part is {R:2} /blah):

www.blah.com/blah.aspx/blah

the browser is redirected to:

www.blah.com/blah//blah

However if I enter:

www.blah.com/blah.aspxblah

the browser is redirected to:

www.blah.com/blahblah

How can I stop this duplicate forward slash from being present in the redirect?

Answer 1

It seems that the issue was only present when run locally in Visual Studio 2017.

When installed on a test and production server the double forward slash was not present... how bizarre.