Use PayPal Auto-Payment with Caution: Risks and How to Cancel
For convenience, most payment tools like PayPal, Alipay, and WeChat Pay offer an automatic payment feature. For instance, if you purchase a monthly VPS via PayPal, the billing date requires renewal every month. Using the auto-payment function solves this problem conveniently.

The Bug of Duplicate Charges
Whether due to a bug in PayPal's recurring billing system or the merchant's system, this function has a high probability of causing duplicate charges. I have encountered this issue more than once, and it has happened with different merchants.
- The first time was with HostUS's recurring billing (WHMCS system).
- The second time was with ServerStadium.
In a recent ServerStadium bill, I encountered the duplicate charge issue again, as shown in the screenshot below.

Although submitting a ticket and communicating with customer service can result in a refund, it wastes time and communication can be inconvenient. In the future, I will opt for manual payments despite the extra effort.
How to Cancel PayPal Auto-Payment
You can cancel recurring payments in "PayPal Settings - Payments - Manage Automatic Payments." If you see merchants you haven't used for a long time or unfamiliar merchants, you can cancel them here.

Conclusion
PayPal auto-payment does not always result in duplicate charges; it may be a bug occurring under specific circumstances. For example, if you initially did not have auto-payment enabled but later clicked "PayPal Subscription" to complete a bill payment, the system might trigger another payment from the auto-payment setting, resulting in a duplicate charge. In any case, regularly checking your PayPal auto-payment settings is a good habit.