OSX 1.16 Freezes/Hangs at 99.722% often

[KBeezie]

Right now (for the 3rd time today) the OS X version (32bit and 64bit both do it on OSX 10.7.5) is stuck at 99.722% , it's not consuming any CPU right now and simply shows as not responding in the activity monitor.

Attached is a sample of the process from activity monitor, and it usually seems to happen if I enable something like fog or ambient occlusion, especially if I'm doing a network render, the windows clients all report as finished rendering.