Appears to be a bug in the latest version of WD (Build 47).
On the bottom graph on the WD Main Screen the UV value is not not being displayed correctly, but is displaying what appears to be the Heat Index instead (see attached image). If I use the mouse cursor across the graph the graph displays UV correctly just until the next minute update of the screen occurs when it returns to displaying the Heat Index again. The UV value also seems to display correctly when the screen captures are made (in my case every 15 mins).
problem will be with a certain combo of settings
I will need a copy of the wdisplay.ini file and the last31daysdata.inf data file, to duplicate and fix
(I did fix a problem with the heat index graph mouse position but that must have upset things when set to plot uv)