No, DW is not producing links like this.
i fond in my log some not-found pages wit this request string error.
So DW should replace this special characters ?&= before it cuts the request string to $ID $IDX $ACT..., i thing it should happen in getID() function.
also files with special characters like äöü are in this case not found.
Im not sure it is better to replace only ?=& or urldecode the complete request string before using it.
But i am not sure, if this is a new m$ bug in IE7 or something else, which encode all special characters (non letters) in the request in %-code. Or perhaps it colt be too a broken bot/harvester. I fund not so many requests like this, but is seems not to by a bot/harvester. Or this Browsers maybe found an follow somewhere a link with this wrong encoding. (no referer percent, can not check it..)
The bugfix (if so, it fix a bug outside of DW) fix the problem with some Browsers/Requests, witch url-encode the complete request string, before access on the page. So makes DW again a bit more stabile, and user are not see a 404 in this case.
If you Check your logs, you have no not-found pages on your site with this problem?
No problems now with unicode languages? (i check this with äöü, DW encodes the filenames in ulrencode, and decode it again correctly at reading. But access form outside cold by a problem, maybe if they not obey http://www.w3.org/Addressing/URL/uri-spec.html
... if you find no such problems, with your many accesses, its maybe a rare bug and can by ignored, (i only report if i find something suspicious to help bugfixing ;)