It's not strange because ripgrep doesn't understand non-UTF-8 data (unless there's a UTF-16 BOM, in which case, ripgrep will automatically understand it). But you can tell it to:

    $ echo $'O\xF0uz' | rg -E iso-8859-1 '^.{4}$'
    Oðuz

The person you're responding to has been trolling in this thread (and others) by twisting words and claiming multiple false things. When I've fixed their errors, they don't acknowledge them as mistakes and just keep on twisting words.