I first noticed this when trying it with some of the Acustica plugins that still work otherwise (with normal interface) in the Master Section. They crash if generic interface is used in the Master Section. The crash also happens with TDR Kotelnikov (VST2) with generic interface in Master Section. Doesn’t seem to happen with any other plugins I’ve tried so far but I haven’t tried very many.
It also seems to happen with these plugins in earlier versions of Wavelab 9, but there they just hang forever.
Doesn’t seem to happen in the montage.