As a result of the problem I was encountering related to this post, I switched from using the Start10 style search to Start11 style. I noticed that Everything Search results using the Start11 style were not returning expected results. Further testing showed that the Start11 results do not match a search performed in the Everything Search app but, switching back to the Start10 search style, they once again matched.

The bigger problem here is that the Everything Search results displayed using Start11 style are not very good in many instances. For instance, searching for a spreadsheet file with a specific word in its name will return that file at the top or near the top of a native Everything Search and also a Start10 style Everything Search. However, when Start11 style is enabled, that same search now only returns folders whose names don't even contain that search term. I have to basically enter the exact filename in order for the search to return that file now.