On this suggested edit, the user (same userID) is having to suggest an edit on his own answer.
Is there something I'm missing here?
This happens when people write answers using cookie based accounts, if you lose the cookie then you become completely disenfranchised from the account. People usually figure out that this happened because they didn't register, go ahead and do so and then contact us for merging if the system didn't catch on.
Fun fact: There was once a user on Stack Overflow that visited once every few days to answer Prolog questions over a year long period, each time creating a new unregistered account. When we finally got them all together, and he indicated that he wanted them merged, he came out with almost 10k reputation.
We've since gotten much better about detecting when this happens and fixing it silently, but occasionally folks use a different email (which may have the same gravatar), or something else about the accounts prevents the automated merge from taking place. These go into a special accounts queue, where we (employees) review clogged merges daily and make sure they get done.