Yes, Etsy has some product tag limitations. When adding a new product from Printful, be aware of these tag rules:
1. The character limit for a tag is 20 characters.
2. The max tag count you can add when pushing a product is 13 tags.
3. Tags must be unique. Don't use the same tag twice for one product.
4. Don't use special characters. We can't precisely define all special characters. Sticking with Latin alphabet should ensure there are no problems!
If a tag doesn't follow these rules, it'll be skipped and the others will be used instead. Adding or changing new tags can only be done by readding the product.