Sorry, I do not have the sensor you are testing but I remember a thread dealing with it. Perhaps you need to look at the pull-ups affecting your I2C sensor. In the link below, @RWB pointed out the following:
The Argon has 13K pull ups built in on the I2C pins.
You might check out this thread:
https://community.particle.io/t/bme280-temp-sensor-predictable-error-in-reading/57498/39