Cast member name doesn't appear in drop-down menu when trying to add

I have repeatedly come across an issue - I'll go to the edit page, and under "Cast and Crew" choose Self to add a credit (for documentaries).  Oftentimes, I will type in a name that has a page on IMDB but I will not see that result in the drop-down menu of possible matches.  I often get names with very little commonality, when the name i'm looking for already exists but doesn't show up.  Sometimes I will get a few instances of the name, but not the correct one.  I could choose either

But then I search for the name and it indeed does exist as an official page on IMDB (sometimes it is a name with multiple instances (different people with the same name) - and I have to figure out which one it is, but the right one does exist.  Why doesn't IMDB give me all the actual matches as an option instead of a bunch of other names?  While it sometimes does this, it is definitely not consistent.