Comment 1 for bug 1432935

thanks for the report!

This was brought upstream to ntp via:

(4.2.8p3-RC1) 2015/05/12 Released by Harlan Stenn <email address hidden>
* [Bug 2745] ntpd -x steps clock on leap second
   Fixed an initial-value problem that caused misbehaviour in absence of
   any leapsecond information.
   Do leap second stepping only of the step adjustment is beyond the
   proper jump distance limit and step correction is allowed at all.

That is in Xenial and Yakkety - setting to fix released.