How did you choose to install Cubase? For the current user or for all users?
Unfortunately Cubase installer never uses the choice which was initially made, which can end up in a folder mess with every update if you do not remember your first choice and then may change from Every / All Users to the current.
I found now the Flux vstsound file in my profile path but somehow it cannot be loaded or accessed. It seems as a bug like HSE does not like the Roaming profile path 