Web Adi additions: Rows uploaded successfully but not all show up in Prepare Mass Additions

When attempting to upload asset data using Additions Web Adi, all rows (350) upload succesfully.

But when we check Prepare Mass Additions form only 348 records show.

We delete all rows and attempt again to ensure all rows show up in Prepare Mass additions. But each time a few rows are missing, yet Web Adi says all rows uploaded successfully.