RichardBarrett
commented
4 years ago I've found the problem and it relates to the default DuckDuckGo query URL on the browser settings page under Privacy and security > Manage search engines. There's an 'ed' at the end of the Query URL that shouldn't be there. The workaround is to copy the DuckDuckGo Query URL, omitting the offending 'ed', and then 'Add' your own entry for DuckDuckGo using the copied URL and make your new entry the default search engine.
This isn't an extension issue as I have tested for that. When the default search engine is set to DuckDuckGo, ed characters are appended to the address bar search string. This only happens when DuckDuckGo is the default search engine. For example, searching for NASA in the address bar will return the string nasaed in the resulting DuckDuckGo search box.