Looking at the photos it finds using the "ace" keyword and I found a few things. First, it found photos with the keyword "face," which makes a lot of sense because the letter combination "ace" is contained within" face".
It also found all photos that have they keyword "chandler". This doesn't make sense. Although it contains the letters A, C, and E, they aren't consecutive, so it shouldn't find it at all.
What makes the least sense is that it found photos with the keyword "Germany," which doesn't have the letter C at all.