Etsy refused to save this product because it counted two of its tags as the same tag.
Why it happens
When Shuttle sends a product to Etsy, it combines tags from up to three places: your Shopify tags (when Transfer Shopify tags is on), your Add custom tags list, and the Shopify metafield named under Tags from metafield. Before sending, it removes tags that repeat exactly or differ only in capital letters or extra spaces.
The error can still appear when:
Etsy reports a repeat among tags that Shuttle did not treat as the same. Compare the product's tags for two that mean the same thing but are not spelled exactly alike.
You applied tag suggestions from AI Discovery to Etsy. Those tags are sent as they are, without this check.
How to fix it
After a transfer or update:
Open the product in Shopify and look for two tags that mean the same thing but are not spelled exactly alike. Remove one of them. Or, in Shuttle, open Settings, then Products, then Shopify → Etsy, and add it under Exclude tags in the Tags section, typed as it appears in Shopify. If your Products page shows a Transfer settings link instead, the same options are under Product Tags there.
In the same Tags section, check Add custom tags and the metafield named under Tags from metafield for the same kind of pair. [TYPE], [VENDOR] and [CATEGORY] become the product's type, vendor and category.
Transfer or update the product again.
After applying AI Discovery suggestions:
In AI Discovery, open the product's suggestions, untick Tags, and apply the rest.
In Etsy, open the listing and edit its tags yourself, keeping each tag only once.
Still seeing it?
If you find no pair like this and the error comes back, contact support and tell us which product it is, so we can check its tags with you.