I sold https://www.zazzle.com/jazzy_and_modern_trumpet_business_card-256729086334136089 several days ago. A day or so later, the customer came back and bought a luggage tag with the design from the above business card transferred to it. The puzzle: Nowhere on the the business card display page does the “transfer this design” facility appear. How on earth did he manage it?
Can’t recall the product, but I was similarly baffled as I had the transfer option disabled on a design that was transferred to another product (and sold last year).