Sorting not working as expected?

Hi,

I'd like to load a list of all files in the same folder, and sort them, for example, by Date Taken. However, when I click on the Date Taken column name in the 'Rename Files' window, it change the order of the files, but don't really sort it. I noticed similar behavior with some other columns, like Error or Error Code. Even if I right click on a record and use Sort by, the effect is the same.

The goal here is to group all files that have the Date Taken in the top or the bottom of the list so I can mark exclude them.

Why the sort works for some columns but not for other?

Thank you,
nelsonwcf