Hey Tuan,
Just experienced this: a person paid by paypal while the event was still open. Paypal decided to delay the payment as they needed to check something. EB registered it as not completed paypal payment. Meanwhile, the event got full and the event closed as it was full. The person who paid via Paypal got their money released from Paypal, the user got set to ATTENDING in the already full event and suddenly the event had one person too much in the event...
Any way to solve this?