No, Fusion Client SDK Gateway and Media Broker processes are not adversely affected by the additional Leap Second. Servers observing the Leap Second may include logs with the following time stamp:
A Leap Second is an occasional one-second adjustment to Coordinated Universal Time (UTC) to keep its time of day close to the 'mean solar day'.
The next Leap Second will be at:
Mid-night - 31st December 2016
Further Leap Seconds are yet to be announced.