I have had this problem with Brave in the past, and it has now returned to haunt me.
With DuckDuckGo as my search engine, every search I enter has “ed” appended in the DuckDuckGo page and search bar that DDG presents.
For example, if I enter the two words
in the search bar, the DDG results page presents me with a search term of
and the original (Brave) search bar displays
I started using Safari for a while, some months ago, and I have been back with Brave for a few weeks, and now it has suddenly recurred.
This problem does not occur with DDG in a Chrome window.