Filter and Slicer Showing Duplicate Values

[random1234]

Hi all,

I have come across a bit of an oddity. Recently, I have noticed that one column, when used as a slicer or filter, is showing duplicate values.

However, if I explore the data in Table view, it shows 4 distinct values:

Additionally, if I run a DAX query on the column, it also shows only 4 values:

I have tried trimming and cleaning the column. I have also tried replacing some hex characters at the suggestion of another thread, but none of these seem to have any impact. 

I'm at a bit of a loss here, so any suggestions or insight are greatly appreciated!

[jgeddes]

If you have not done so already, go into Power Query and get a distinct list of values from the column in question. 
One of the easiest ways of doing that is populating a blank query with

= Table.Distinct(Table.SelectColumns(tableName, {"ColumnName"}))