Steve…
Just looking at mine.
RH on my wall mounted weather station (pretty accurate) is showing 64%
Enviro+ just below it is showing 27%
Wonder if it’s the heat from the Pi that’s messing with it?
Done an experiment…
Mounted the enviro+ on a HatHacker board. The ribbon cable has moved it 6" away from the Pi.
RH on the Enviro is now within 4% of my other machine so it looks like the heat from the Pi was the problem.
Also, the RH reading is now stable (it was slowly drifting negatively before)
Or use a fan to blow on the sensor board from the side - will both cool the cpu board and remove the heat from the sensors. Would probably be beneficial for the temperature measurements at the same time. This has tended to be my solution in the past.