So it was in your divorce agreement, but wasn't good enough?
Basically yes. Although the wording was good enough for the County/State, it wasn't good enough for the company holding my 401K. I also want to add, I have a second rollover IRA with another company. They had no problem removing my ex as a beneficiary based on the wording of our divorce agreement.
If you can determine the specific information the financial company is looking for in advance, you can add it into your divorce agreement and you should be fine.