Hello @Chase_Schwalbach!
I checked the automation and it shouldn’t fail, I think it is indeed a bug.
Normally the an automation fails when this happens:
In your case it doesn’t apply so I think It should work. You should contact support through the “?” button at the bottom right corner of your doc.
As a workaround you can add a button column in your Audit Table that adds to the History and updates the row, you can disable the button if Diff is Blank and set the automation to press the buttons in the table.
I copied your doc and tried this approach and it worked as expected.
And the automation it set up like this:
