Are there any specific conditions for UnionPay transactions?

Yes, there are. For the first transaction with UnionPay, the recipient must verify their UnionPay Account. 

Here's how to verify a UnionPay Account.

1. Recipients will get an SMS containing a link to verify their account. Recipients should click on the link to verify their identity.
2. Recipients must provide their personal details, including Chinese name in Chinese characters, Chinese National ID Card Number (18 digit), ID Expiry Date, and select their occupation from the available drop-down list.
3. Upload a photo of the Chinese National ID Card of your recipient (both sides of the ID card should be uploaded in JPG format). This is required for first-time recipients to register their account. 
4. Recipients must provide their bank account details, including their China UnionPay Debit Card Number, mobile number used to open the UnionPay virtual account, and SMS verification code or debit card PIN code. The recipient also need to enter the shown CAPTCHA and agree with banks the terms and conditions.
5. After completing the verification process, the recipient will receive the money in a matter of minutes.

It should be noted  that the recipient only needs to complete the verification process once. If they fail to complete the verification within 72 hours, the transaction will be cancelled, and the money will be refunded to Coin Flip. Besides that, if the recipient's ID card or bank card has expired, the transaction will be put on hold, and the money cannot be refunded. The transaction will only be processed once the recipient updates their ID card or bank card.