LM75A: Temp Error Issue

Part Number: LM75A

Hi

My customer is adopting LM75A solution and schematic is as attached. Register are all default value. Now there is an issue when doing temperature box experiment. Setting temperature box change rate 25C/hour, so about 0.5C/min. When temperature box shows -30C, however the readback value is -66.5C. I2C waveform is as attached. Register 0X00 is0XBDFF, temp is -66.5C. Could you help comment possible reasons or what i can test to get the reason? Thanks!