Uploading to dataset, says 100% success, but rows missing

I have been able to upload week over week the same way for a long time. Usually if rows are not imported it is reflected in the summary, along with what rows were excluded.

This week, I tried to upload the same way I usually do, and any row that has a value in the first column is not included in the dataset, even though I can see it in the table.

The summary after import says 100% success for ~11000 rows when its missing ~2500 rows, all which have data in the first column. Any Ideas? They are both strings.

Fixed, Date column forgot how to interpret dates? I wonder why it didnt tell me failed import on those rows.