I have a few plugins that have ‘offline render’ settings where you can set the plugin to engage higher quality when offline rendering. Leapwing DynOne 3, TDR Slick EQ M etc. It appears that Wavelab is not telling the plugins to engage this mode when rendering. Render times are no different when these plugins are set to do this. However when I manually set the plugins to the higher quality settings then render times dramatically increase. I haven’t yet done any null tests to check audio as yet.
Tokyo Dawn was VERY responsive in fixing an issue in the newly launched VST3 version of Kotelnikov. I would contact their support to see if they can see why the offline render settings are not being used.