Enviro+ Oxide Level slow climb

I have found that if I run the Enviro+ with the supplied python examples for an extended time (hours), that the oxide reading just slowly climbs. It doesn’t ever seem to drop off. I understand that the device takes time to warm up but watching it go from 7k ohms to 18k ohms in a matter of 2 hours on an almost linear curve seems very fishy especially with the data sheet saying 20k ohms is the max. Could have just gotten a faulty unit? Is there a firmware update?

As an update the readings from the python library have stabilized but it is above the specs on the data sheet for the oxidized sensor on the gas sensor. It lists 20k as the max value which correlates to 10 ppm. I have been graphing for a bit now and it does seem to be reading something but it is always in the 22-24k ohms range. Just wondering again if there is some firmware or a library update that is needed or if I have a bad unit?