Safari locale doesn't match system locale
I noticed multiple sites pre-selecting the wrong country when I visit them: The Netherlands instead of Belgium. Today I checked this in the Javascript console and my navigator.language variable is set to "nl-nl". This of course explains why this is happening.
However, my system locale was left unchanged. It's still configured as Belgium - Dutch. And the Terminal environment is also correct: LANG=nl-BE.UTF-8.
I don't know when this came to be like that, but I suspect one of the last Mavericks updates. I'm running 10.9.4 with Safari 7.0.5 (9537.77.4). Anyone else also facing this issue and found a solution? I already tried trashing the Safari preferences but that didn't help.