Google announced that beginning on September 15, 2021 Google will enforce correct unique product identifiers (UPIs) for your products uploaded to Google Merchant Center, even for free listings. Google said it is “expanding this enforcement and applying it to products listed in free listings.”

Google explained that “providing the correct unique product identifiers (UPIs) for your products ensures that Google recognizes them and can provide optimal customer experience.” Some examples of common unique product identifiers (UPIs) include Global Trade Item Numbers (GTINs), Manufacturer Part Numbers (MPNs), and brand names.

Google said in “order to unify the enforcement of UPIs across programs, specifically the enforcement for multiple different products that use the same GTIN, we’re expanding this enforcement and applying it to products listed in free listings.”

Starting tomorrow, September 15, 2021, the following enforcement will apply to products shown in free listings:

• Different products that use the same GTIN with the same variant attributes will be considered ambiguous and will be disapproved.
• Variant attributes include condition [condition] and multipack [multipack] for all products, as well as color [color] and [size] for apparel products.
• If a group of products are identified as duplicates, only one will remain active and eligible to show in free listings.

In March, Google pushed the importance of unique identifiers for products and in April began enforcing unique MPNs.

Forum discussion at Twitter.