Past 7 days, about 3.5% of transactions need manual fixes right after the 1 pm batch in our high-volume retail import. When I import the noon POS CSV and review in Excel 365, the tax column shifts one to the right on rows with a promo code, so 15–20 lines per batch end up mismatched. It started after we added a 2–3 step dedupe in Power Query, and it keeps showing up even when the source looks clean. This belongs in What’s News in Data Entry: recurring entry mismatches after routine uploads.
I ran into the same shift after a PQ dedupe that grouped rows and concatenated promo codes - the comma in the combined promo made Excel treat it as a new column, so Tax slid right. The fix was to force Promo to Text and either replace commas (Text.Replace on Promo) or wrap the field with quotes (Text.Quote) in the query before export; if you used Group By + Text.Combine on Promo, that’s likely the culprit.
I hit the same slide after a Group By that used Text.Combine on promo codes; switching the join to a pipe and then forcing quotes on the Promo field fixed it. Final step in M: Table.TransformColumns(#“Grouped”, {{“Promo”, each Text.Quote(_), type text}}) - after that, Excel stopped pushing Tax to the right on promo rows.