It looks like Microsoft has finally removed and/or broken support for ActiveX Flash in Win10 1809 (and 1903). This prevents installing LDD because the LDD installer checks for Flash, tries to install/update it, and always fails. It is not possible to install Flash separately as was the old fix. ActiveX Flash simply doesn't exist for Win10 any more.
Fortunately, it does not break existing installations. So if you already have LDD installed, make sure you're up to date before upgrading to Win10 1809.
Does anyone know someone who's on the LDD team who can work on updating the LDD installer to not have the Flash requirement?
Thanks,
Terry