The first thing to realize is that the Sponsored Links search is unrelated to the keywords chosen by the advertiser to display the ad. Instead, the results shown are the ads that include the query words in the ad text. That's why you'll see only one or two ads at google.com/search?q=raccoon+squirrel (because it's not a great keyword to advertise for) but lots of them at google.com/sponsoredlinks?q=raccoon+squirrel (all of the ads shown contain those two words).
So if the Sponsored Links search is unrelated to the keywords and shows just the ads that have the query words, that's why it uses the default destination URL for the ad rather than the specific ones for the keywords.
There's some information on Sponsored Links search at [adwords.google.com...] but it's not really fully explained.
but its functionality changed around June 2008
Didn't know about that.
So if the Sponsored Links search is unrelated to the keywords and shows just the ads that have the query words
That would make sense. But in my case, I search for the same exact keyword that I target.
The phrase is both in the ad title and in the keyword list.
I understand the idea of matching ads by ad text, as if ads are documents. And that's actually a pretty good idea.
But unfortunately, it's messes up my tracking.
Fortunately, there aren't that many people running queries on the sponsored links search. (yet?)