The final column of DataTable is always returned when using "Get Data Table Column as String" blueprint node.
"Get Data Table Column as String" Blueprint node is new as of 4.19
1 - In a 4.19 project
2 - Create a Struct with Name variables that match your Columns in DataTable (In the attached CSV Columns are [Activates ,Deactivates, InstructionText])
3 - Import your CSV - Select the Struct you just created on Import.
3 - Attempt to use "Get Data Table Column as String" Blueprint node with "Activates" or "Deactivates" as Property Name.
4 - Observe Final Column is always returned.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-56017 in the post.