Shuttle shows this message when it skips an Etsy listing on its way to Shopify. It found a Shopify product with the same SKUs as the listing, but that Shopify product is already linked to another of your connected Etsy shops. Nothing was created or changed in Shopify.
Why Shuttle skipped the listing
A Shopify product can be linked to only one Etsy shop at a time. When Match products and variations by SKU is on, Shuttle looks for a Shopify product with the listing's SKUs before it creates a new one. If that Shopify product belongs to another of your Etsy shops, Shuttle skips the listing. It does not create a second copy in Shopify, and it does not link one product to two shops.
The message can appear in these places:
When you transfer a listing yourself, as a Linked to another Etsy shop notice
During a queued or bulk transfer from Etsy to Shopify
When new Etsy listings are transferred to Shopify automatically
What to do depends on which Etsy shop should sell the product.
Link the Shopify product to the Etsy shop that got the message
Moving the Shopify product to the Etsy shop that got the message links it there and removes the link to the other shop. Moving only changes the link in Shuttle. The listing in the other Etsy shop stays as it is, and the product's reviews stay with it.
Make sure the Etsy shop that got the message is your active shop. If it is not, go to Settings > Account > Connected Shops and click Activate next to it.
Open Products and choose the Shopify → Etsy tab.
Turn on All Etsy shops. Products linked to your other Etsy shops now show in the list with a label naming their shop.
Find the Shopify product and click Move to Etsy shop on its row.
Under Move to, choose the Etsy shop that got the message. Then click the move button and Confirm move.
Once the product has moved, Shuttle tries to match it with your listing in the background, using your matching settings. If the listing is still not matched after that, open the Etsy → Shopify tab, find the listing, open its More actions menu and choose Match to Shopify.
If you no longer sell the product in the other Etsy shop, deactivate that listing in Etsy. Moving the product does not change it.
Sell the product in both Etsy shops
To sell the product in both Etsy shops, each shop needs its own Shopify product, so the listing needs different SKUs. Shuttle then finds no Shopify product with the listing's SKUs, so it creates a new one.
In Etsy, open the listing and give every variation its own new SKU that no Shopify product uses yet.
Transfer the listing to Shopify again.