Hello all!
With the old inventory templates eventually being phased out, we thought we'd take it upon ourselves to try out the beta template option for listing new products in preparation.

We managed to fill it out with little difficulty and were in the process of uploading the .txt file, when we encountered the below error before submission:

After reviewing spreadsheet several times, even starting over at one point, we have no idea what could have caused this.
As one would expect, we've had no luck in getting Seller Support to understand the issue, they keep trying to explain to us what an inventory file is and how to upload them which in the traditional sense we are more than aware of.
Has anyone else experienced such an error, or similar difficulties when dealing with the new beta templates? It seems like another case of Amazon trying to fix something that wasn't broken in our opinion.
Thanks