Updating this thread regarding Wallpaper Engine not being compatible with Start 11.
I have sent several messages in various ways to the developers about this but I haven't received any answers so I would assume they don't care.
TLDR
If you want to keep using Start 11, unless Stardock wants to look into this issue themselves - be prepared to lose your beloved wallpaper app in turn to use Start 11.
Its not a slight on WPE, they make a fine and very popular product, but it's not the 1st time we have had reported issues like this when WPE is used.
That said, when this happens, if you restart Windows Explorer, does it resolve the issue?
Sean Drohan
Stardock Product Lifecycle Manager