I’ve never heard of a way to get the uncorrected readings from WF gear. In the past they always reported a corrected reading but we could never get a way to see what (if any) correction was being applied.
One old thread is at Calibration questions - #15 by WFstaff if that helps any, and the whole thread there might help explain. Way back during the beta testing phases a number of us reported seeing the Tempest reading high in bright sunlight and it was pretty clear the case heated up eventually in calm conditions. I remember doing some comparisons to other gear back then and this was always the case. They read fine at night after things cooled off but read high when the sun hit the sensor, which is another reason I liked the Air+Sky two sensor approach they started with.