Here's my guess on this one:
A while ago, the Discovery team made some improvements to prefix search, where they automatically handle certain misspellings (making it no longer a strict "prefix" search). For example, searching for "Barck Obma" actually produces the correct result, without a redirect. In fact, I can no longer seem to construct an API query that produces a suggestion anymore. It's possible that this has been superseded by the fact that prefixsearch now automatically returns the "suggested" spelling, and our handling of the suggestion may even be safe to remove.