[Terabitten]

You have to understand how the SSA databases are set up. There is one database for identifying information, and another for payment info. The payment info database also has dates of birth and death, but THE TWO ARE NOT DIRECTLY CONNECTED.
In other words, all this means is that the ID database didn't get fully updated, likely back in the paper file days. The payment database is much more accurate, always has been.

[sheana]

Most of them are probably like when my mom passed. I called them and told them she had passed and the date. They backed out the check they had just deposited into the checking account and asked me to send them a copy of her death cert. Since they had already stopped her checks and took the last one back I said screw them, I’m not going to the trouble to send them jack. So she is probably still on their rolls even though there’s no money going out.
I’d bet very few people take the time to copy a death cert and send it in to them.