And that is where the complexities arose that Judge Griesa seems not to have understood.

The order he issued earlier this year said that — assuming Argentina does not make good on the old bonds — it should not make interest payments on the exchange bonds, and banks should not help it do so. That sounded as if it covered all the exchange bonds, even those not issued under New York law.

But the opinion explaining the order discussed only the dollar bonds issued under New York law. It ignored the existence of other exchange bonds.

So did the ruling apply to those other exchange bonds, including those issued under Argentine law? Would a bank that processed interest payments on those bonds be in trouble with the judge?

Citibank’s Argentine branch, which is the trustee for bonds issued under Argentine law, some denominated in pesos and some in dollars, asked the judge for a clarification, and on June 27 he provided one. Citibank could process interest payments on those bonds. They were not covered by his order.

This week’s hearing was largely about changing that ruling, and the judge initially made it clear that he saw no reason for a change. He saw the bonds as domestic ones, owned by Argentine citizens. “From a practical, common-sense standpoint,” he asked a lawyer for the hedge funds who was trying to have the order modified, “why do they have to get dragged into this?”

It turned out that he did not know much about those Argentine-law bonds. He said his June order provided “a rather minute exception” to his original ruling, and told the hedge funds’ lawyer, Edward A. Friedman of Friedman Kaplan Seiler & Adelman, “It is my understanding that the bonds being talked about in your motion are not part of the exchange.”

Told that the bonds in question were exchange bonds, and that they accounted for nearly a quarter of all the exchange bonds, he said he had not realized that and reversed course.