Apple has used a new Intel CPU on their MacBook Air, which has a feature that lowers the CPU speed to match the software using it. When there is less running software, the CPU will set its speed according to the needs of the running software and will not run at its maximum speed.
The Icon audio interfaces are designed to work with computers running at full speed, so when running on a processor set to a slower than normal speed, the audio may not be processed fast enough to keep up with the interface. This can cause the audio to 'back up', and might create some audio stuttering or drop-outs for interfaces running on these systems.
The only solution currently available for this problem is to increase the recording and playback buffer sizes in your software of choice until these errors stop.