Even that never really happened, did it? Madoff was never not able to make a payment.
His kids reported him to the police before they could be found out by anyone else. Of course, as part of the reporting, they also got immunity from the consequences of the company they worked for being an elaborate ponzi scheme.
I suspect it's highly likely that this was a scheme they came up with to ensure that no one in the family, other than Madoff himself, would have to suffer the consequences of their crime.
There were no reports of Bernie Madoff not being able to repay investors until the day he ran out of cash.