Liquid Mix must process offline bounces in synchronisation with its DSP hardware, and it takes special care in doing this during offline bounces. Liquid Mix is capable of offline bounce at a speed 10% faster than real time. Most DAW programs manage the selection between realtime and offline bounce automatically but a few require special attention. For example, MOTU DP5 and Ableton LIVE users should tick this box to guarantee perfect offline bouncing.
In general, if you have any problems with offline bounces on the Mac, try working with this box ticked. If you have any problems working in realtime, e.g. CoreAudio runs out of time in Logic, make sure this box is not ticked.