I occasionally find titles that are in the database but are not returned from a search on that exact name

Several times in the past few years, I've searched for titles that do not come up in search results but that I later find are in the database under the exact phrase I searched for.  The most recent example is "Taking Tiger Mountain (1983)."  This movies is in the database under that exact title

https://www.imdb.com/title/tt0086409/

But a title search for it does not return that result (although it returns titles connected to it).  This is actually a well-known experimental movie starring Bill Paxton.  I found it easily by searching for his name.  Why can't I find it with a title search?