How to force uniqueness of cell in Google Spreadsheet with non-Latin text in cell?

I have Kannada text in my column and it's not working, but it worked fine with Latin text before. Kannada text is from a region near India. Here is my spreadsheet, there are too many rows to include in this post.

word    frequency   ಮತ್ತು   71520   ಈ   40233   ಒಂದು    25255   ಎಂದು    17046   ಇದು 15032   ಅಥವಾ    14527   ಹಾಗೂ    13709   ಅವರು    12979   ಎಂಬ 10660   ಮೇಲೆ    10581   ಅವರ 10204   ಆದರೆ    9271    ತನ್ನ    9090    ತಮ್ಮ    8768    ನಂತರ    8672    ಮೂಲಕ    7645    

The validation rule is:

=COUNTIF($A$2:$A,"="&A1) < 2

That is, on the second row onward, validate that no two cells have the same value. I double checked that the cell that has the red flag on it doesn't have a duplicate, and it doesn't, so something must be off with the way unicode values are calculated in that expression or something, any ideas?

I learned how to do this in the first place from Forcing uniqueness in a Google Spreadsheets column