Remember that I always use exact search, and fairly often I use some of the whiz bang features such as Restrict to Exact names and: Names with Similar Spellings or Meanings. Suddenly, strange things seem to happen.
If I pick Names with Similar Spellings or Meanings, everyhing looks fine in the drop down box but after the drop down box has gone away, the actual option that is set is Use Default Settings. And a search conducted at this point does use the Default settings and gives me millions of matches.
So I click "Default Settings" and change it back to Exact, and all seems well because it has even remembered that I selected "Names with Similar Spellings or Meanings". The only problem is, the over all Exact setting at the top of the Search template has now been turned off.
The problem is mostly repeatable, but not 100% repeatable. And sometimes there are some variations on this basic theme. It acts like whatever is wrong is local on my browser or in some underlying Java or other scripting on my local machine, not something back on the ancestry.com server.