Getting "Unknown error while reading Transactions sheet" every time the plugin loads

A few weeks ago the sync failed part way through. When I ran the sync again, it resulted in duplicated transactions. I deleted the duplicates (the original entries), and ever since I’m getting this everytime the plugin loads:

This does not stop the sync from working.

I’ve confirmed the column headers are unchanged from prior (working) versions, and nothing seems egregiously wrong with any rows.

What did I do wrong? How do I make this go away?

I have not seed this before. Have you reached out to tiller support to see if they can help? They can see things on the back end that give them clues sometimes. support@tiller.com