According to J-Cast, some ATMs of Japan Post Bank placed at Comiket 76 emptied out due to the extremely large amount of the withdrawal by the visitors. Japan Post Bank admitted the incident and apologized for the inconvenience. The ATMs were back to normal in a few hours.
Comiket 76 was held from August 14 - 16. The number of the visitors were 560,000 and set a new record.
Picture of the waiting line of C76 (outside)
The waiting line (inside)