제 상태에 대해서 설명하고 처리를 요청하는 메일을 보냈었습니다. 이후 하루정도 지나 답변이 왔었고 이후 정상적으로 구매가 가능해졌습니다.

메일을 다시 확인해보니 험블의 필터에 걸려 승인이 보류되었던 것 같습니다.  

아래는 제가 받았던 답변 내용입니다.

Thanks for reaching out to us and I'm sorry to hear about the trouble! It does appear that you were accidentally caught in our fraud filters, which is what caused your order troubles. This process does not affect every order, and is not meant to be applied to users such as yourself. We are reviewing its implementation, and I can assure you that this will not affect your ability to order through Humble Bundle in moving forward. In the meantime, I did see you still had a pending purchase of The Incredible Adventures of Van Helsing III, so I was able to verify that order for you. You should receive that download page shortly. Sorry for the inconvenience. Have a great day!