A Qingping CGP22C could keep reporting carbon dioxide at 290 parts per million even as the air around it changed. A correction in the Qingping Bluetooth library stops a hardware-information field from overwriting the sensor's actual reading, following the manufacturer's confirmation of which field carries carbon dioxide.
Separate temperature-and-humidity updates also leave the last real carbon-dioxide reading intact. This is cp296944's first contribution to the repository, with review from bdraco.