Quoting myself. I got this wallet last Thursday or Friday, and was disappointed that it was tied to a different Apple ID. I get it; it was a return to Apple, and somehow, the eBay reseller ended up with it (they had more than 10 when I bought it).
Last night, I attached it to my phone, and this time, I was prompted to add it to Find My. Hmmm. It shows up under my Apple ID now.
All I can gather is...possibly...the original purchaser of the wallet received prompts that the wallet was detected, went into their Apple ID and removed the wallet, thereby freeing it up for me.