There is a thermometer in the 8960 that will monitor temperature and display this error if it detects a temperature change of some predefined delta. From the system menu of the 8960 there is two calibration option. Running these may fix the issue. However, the 8960 can sometimes display this if there is an actual hardware problem and running calibration on the box will not clear it. Running automated tests on a box displaying this error is not suggested because a lot of the power measurements will return with integrity errors, and the Software will consider this an error and show an undetermined for the test.