As designed Changing a Username does not update who liked a post.

[The Dark Wizard]

A user was using his real name for a while and then asked our staff to update his name, after caches have been rebuilt etc, it still shows his previous username under every post he liked.

I don't know if this is working as intended or a bug.

 

[Jake Bunce]

A user was using his real name for a while and then asked our staff to update his name, after caches have been rebuilt etc, it still shows his previous username under every post he liked.

I don't know if this is working as intended or a bug.

As designed, says the K man:

http://xenforo.com/community/threads/likes-dont-update-after-username-change.23893/