I have experienced it twice now with both 1st generation and 2nd generation units. Calls for heat cycle your a/c compressor potentially burning it out prematurely. Here is the thread where others have experienced the same thing. Obviously there is a wiring fault within the base plate but Nest seems to not be able to resolve it. Amazing problem for a $250 thermostat.
Taking a departure from the usual postings and instead providing some links below for the ladies out there and the women in your life, enjoy. Tomorrow, back to business.