Another member reported the same issue with her Android tablet. After trying lots of different fixes, she worked this out:
Where the large RETURN or ENTER key would be on a desktop computer keyboard, Chrome and DuckDuckGo both say NEXT (whereas the Samsung internet browser, which still works, says GO.) I have always used these large NEXT "keys" to do the search, and they've always worked until a few days ago.
So it seems there is some change on the tablet keyboard. I will ask our developers if there is anything we can do to help resolve this issue.