Is my PiicoDev BME280 Atmospheric Sensor faulty?

[Fractal]

Hi Ian
I had previously reported that the PiicoDev BME280 gives a temperature which is 2 degC low. See

Compare piicodev TMP117 and BME280 temperature sensors

There has been discussion about checking the accuracy of temperature sensors but fairly academic without a calibrated reference. We can however compare readings from two sensors. We can also check their drift and repeatability. So I set up a piicodev TMP117 +/-0.1degC and BME280 +/-0.5degC in parallel. Both sensors had initial drift with the TMP117 going up and the BME280 going down but after a minute they both settled down. The repeatability of both sensors was excellent reading to 2 decimal …

I assume the problem is with the libraries but I lack the skills to fix it. If you look at the data sheet it involves heavy programming in C++. I tried the PiicoDev board with the Pimoroni libraries but it brought up an error.
But there are other serious problems with the BME280 relating to humidity - see other posts on this topic.
Remember the BME280 was designed for humidity and pressure measurements. The temperature measurement is included to improve the accuracy of these measurements and that it can be read seems to be incidental.