cgminer is stopping work because one of the cores is too hot. I find that will happen if I haven't done a good job of mounting the heatsink; I'll see most of the chips sitting at 60-70 and one will shoot up to 100. The back and forth with cgminer is something we'll fix in a FW update, but the root cause is bad heatsink contact.
Will look into it but since reported temperature starts at 35 and go to 66 I don't think this is it... Unless we don't see highest temperature reported...