c# - Request.QueryString returns inconsistent values

Question

I am using encoded query strings, but experiencing a problem.

URL: default.aspx?qX81JvYf9eQ%3d-dmVoaWNsZUlkPTE0MTM%3d

On the Page_Load I retrieve the query string using Request.QueryString, but it returns different results on IIS Express and my local IIS 8 server:

IIS Express:
qX81JvYf9eQ%3d-dmVoaWNsZUlkPTE0MTM%3d (correct)

IIS 8:
qX81JvYf9eQ%3d-dmVoaWNsZUlkPTE0MTM%3d%3f

IIS 8 has an additional '%3f'.

Why is this happening? I'm assuming it must be due to some IIS setting somewhere.

Answer 1

The problem was due to a malfunctioning URL Rewriter. Very painful and a lot of time wasted.