Loading Positions with a Valid Grade via HSDL

Summary

When loading Position data via HSDL, I get an error message that I don't understand and haven't seen before.

Content

The error message I get is as follows:

"The line for component PositionGrade with instruction MERGE doesn't include values that define a unique reference to the record."

I've checked Effective Dates for all objects and there's no conflict, I have no clue why it won't load. I'm just using the out of the box spreadsheet loader via the Manage Positions page - "Manage in Spreadsheet".

Any help would be greatly appreciated!

Version

20C