Dataflow Refresh Error with accented characters in data

I am trying to import my data into Dataverse using Dataflows. I am not performing any data change operations other than detecting everything as text. One of the column in my data contains accented characters like 'ē' or Ā, etc and sometimes just multiple dots at the end of string like 'Recap.....'. I am using this column as Key column as it has distinct values only which I have verified using Excel. But when I import the same distinct column in Dataverse using this as Key to update the data, it shows me that key with the same duplicate value already exists even when all rows in this column is unique.