I have a break through of running Rapture Pro in FL12.
By switching fixed buffer size on in the wrapper it works as expected. Neither options in the more box are selected. I don't know what this means though
However there is a weird graphic issue on the VST3 after I come out of the wrapper processing settings the interface is all mixed up The elements / Mixer page appears where the browser should be then the interface (Plugin GUI) breaks up and crashes. (goes back to normal after reloading the plugin.)