With this version:
GNU Emacs 24.5.1 (i686-pc-mingw32)
 of 2015-04-11 on LEG570

On Windows 7 professional,

In scratch buffer, evaluate the following:

(w32-shell-execute "open" "
http://sage/rnd/rndprojects/myproject/Project%20Management/Forms/AllItems.aspx?RootFolder=%2frnd%2frndprojects%2fHNJ%2dHEVC%2fProject%20Management%2f%5fMeeting%20Minutes&FolderCTID=0x01200091670F1D770B314A8F69FA9D507AF4A9&View=%7b6AD90071%2dEB9F%2d4E1D%2d9250%2d282C8580F2F1%7d
")

Now if you check the actual URL sent to the browser, some garbage will
appear at the end of the URL.

If you shorten the URL (to a point), that does not happen.

I verified at least with Emacs 24.3 there is no such issue.

PS: I feel Emacs release quality has been dropping over the years. Wish
this can change. Thanks.