Here's something interesting. Following a post I found on ahk forum, hitting Windows-d key to minimize all windows sets desktop to WorkerW. I tried it and it shows in the spy. Seems to create a new folder then too. So unless somebody has evidence it's broke, I assume it's "working as designed" now. 
Strange goings on.

Strange goings on.








hadn't thought you where still looking for a solution, as imho it's fixed, but I now realize I didn't post that here... sorry