Using an Adafruit BME688 with version 0.6.0 of this lib and the example code, I always get constant readings for humidity and gas.
Temperature and Pressure do slightly change and seem to be correct.
FieldData { status: 176, gas_index: 0, meas_index: 0, temperature: 2222, pressure: 103645, humidity: 100000, gas_resistance: 12917167 }