Unixadm, how much did the temps fluctuate? Do you have any outside influences to attribute the temp fluctuations to? Like wind?
I'm asking because thats the first I've heard of this.........and I just ordered my ys1500 last week.
I have a ys640 and the only time the temps fluctuate on it was when I had a few steam pans in it and I always figured that the fluctuations were due to the blockage of air flow. When this happened, the display temp was always hotter than the actual temp by somewhere between 25 to 50 degrees