I noticed that my solar radiation readings seem to behave oddly. After sunset, when you’d expect the reading to go down to zero, it’d actually rise up to around 100 w/m2 and pretty much stay there through the night, sometimes dropping back to zero for periods of time. You can see that here.
After a perhaps-unnecessarily protracted Email discussion with Davis and a phone call, a replacement sensor was procured.
I installed it Saturday morning (it was starting to rain and snow, so we didn’t miss accounting for much solar radiation), and it seems to be working properly now.