You are exactly correct. The aforementioned thread[0] on Serverfault mentioned timesmearing with `ntpd -x`, as per [1]. It's a fairly well-known technique for avoiding some weird kernel-related bugs on leap seconds.

[0]: http://serverfault.com/questions/403732/anyone-else-experien...

[1]: https://web.archive.org/web/20140221084401/http://my.opera.c...