SHT31 Weather-proof Temperature & Humidity Sensor gives 38°C for 60°C

Hi, 

I have purchased two SHT31 Weather-proof Temperature & Humidity Sensors and trying to place them in an environmental chamber to monitor temperature changes over time. I have connected them directly to a Raspberry Pi Pico (sensors powered by 3.3V) with micropython running the following code:

import machine
import utime
import ustruct
import sys

TEMP_ADDR = 0x44

i2c1 = machine.I2C(0, scl=machine.Pin(17), sda=machine.Pin(16), freq=400000)
i2c2 = machine.I2C(1, scl=machine.Pin(19), sda=machine.Pin(18), freq=400000)

while True:

  # high repeatablility with clock stretching disabled

  i2c1.writeto(0x44, b'\x2C\x06\x4F')  
  d=i2c1.readfrom(0x44, 6)

  # display hex

  print("".join(" %02x" % i for i in d))
  print ("T1 = {:.0f} ℃, RH1 = {:.0f} %".format((d[0]*256+d[1])/1000, (d[3]*256+d[4])/1000))
  i2c2.writeto(0x44, b'\x2C\x06\x4F')
  d=i2c2.readfrom(0x44, 6)
  print("".join(" %02x" % i for i in d))

  print ("T2 = {:.0f} ℃, RH2 = {:.0f} %".format((d[0]*256+d[1])/1000, (d[3]*256+d[4])/1000))
  input()
 

When placing the first sensor inside the environmental chamber at 47℃ and the second one at room temperature 23℃, the outputs from the sensors are:

87 76 52 14 bb 39
T1 = 35 ℃, RH1 = 5 %
 

67 4a 9c 51 ff 3e
T2 = 26 ℃, RH2 = 21 %

When placing both inside the environmental chamber at 60 °C, they both give 38 °C. It seems the sensor is nearly accurate at room temperature, 12 °C lower at 50 °C and 22 °C at 60 °C.  It is far away from the claimed accuracy of 0.1 °C. Is there anything we can fix the problem?  Thanks.