I have been using about a dozen Si7021 sensors for a few years now. It has been operating on all gen3 devices with all the os revisions - I2C - and I have found no trouble. Lately, I have been using the library - Particle_SI7021. The unit I use is:
I have also been using a SHT30 device from Adafruit on an Argon since June of this year - I2C. It is part of an outdoor weather station. It has been working very well. Library is: adafruit-sht31. But, this is only 1 unit on 1 device. Not much history to go by: