I had a similar problem a few months ago, and maybe this is totally unrelated - turned out, after an WD updated in my weather trends rain history all the numbers were either not there or goofed up. Got help from someone on another forum, For some reason in Wd I had to go into the Control Panel, Internet File Creation & Uploads, I believe Setup Page #1, select Set for File #9 trends.gif — for some reason this file had stopped being created – so I had to have it created again – but I did not have to set anything to upload the file.
Worked for me, but again may be way off base.