Last modified: 2012-09-06 20:54:26 UTC
In source of [[Special:CentralAuth/Liangent]], I see: data-centralauth-mergemethod="login"
Many extensions including Translate does this. There isn't any realistic work around as far as I know.
I'm taking the initiative to mark this a 'wontfix'; the worst case you'll find is validators whinging, while it'll continue to work in all browsers.