Sorting --not consistent

I am having a strange sorting problem with work files. I work with files that contain thousands of entries and sorting is not working correctly. I have attached the file, I have deleted most of the columns to protect the data which belongs to my boss but the three columns that it is sorting by are there.

The order of the sort is as follows: Town Name -> Name of Bank -> Year

I know that not all the names are correct so that would screw up the order but an example is in rows 1730-1734

It seems like even when the names are identical 1923 ends up at the end instead of after 1922 (and before 1924 ;) ). Now, if I copy paste the name from the first row (1730) and paste it all the way down and then resort, the problem is fixed....but as you can see it looks like the names are identical already so I'm not sure why I have to copy paste (it is consistently 1923 with this file, each file that I work with has a different but similar issue). I'm not sure if this is a user end problem (the data was exported so I'm not sure if the data was entered differently)...but it looks like the names are identical and that the sort (at least for this section) should be correct.

Please let me know if this is a user end problem, then I can make sure it doesn't happen again. Thanks!

I've done a quick "if" statement to see if the names are the same and they check out fine....this makes the sorting issue even more confusing. It's showing "true" that the names are the same yet they don't sort correctly unless I drag the top name to the end and then sort again.....so weird