If you changed product type or category (not product title) then this may be the cause. Without being able to look at your store in totality this would be hard for me to identify the root cause.  Can you try filtering the report using product, sku, o...

Solved:  Shopify product types aren't applied retroactively to products, so when you add the product type any products sold from that date forward will have the type attached for reporting. Any products before that date will not have product type att...

Has this been resolved? I am running into the same issue.