I have been running FreeNAS for about 8 months without any problems. I just upgraded to FreeNAS-9.3-STABLE-201601181840 and set up the first jail a few days ago, and have seen the issue in this thread three times. FreeNAS is hosted by a Linux based virtual machine, on an enterprise grade HP ML350 G5. Mainly I wanted to point out that I have drastically different hardware here, which indicates this might be a software problem.