If you look at the final link that DuckDuckGo redirects you to when you search for "'!wot http://www.example.org/" (https://www.mywot.com/en/scorecard/http://www.example.org), you see that the "http://" part of the query is still there. Since DDG didn't filter out the "http://" that caused the original problem, I would guess then that the change was on WOT's side, not DDG's.

You're correct though in that we're not sure, so I've edited by original post to reflect that.

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