I have the same question / issue. Just got at LIne 6 GX (small interface) and POD Farm 2.59, all of which seems to work fine standalone.
However, when I insert any of the POD Farm plugins (64b) inside of Cubase (9.0.40 Build 292), they produce no sonic effect.
Cubase has found the plugins, I can insert them, I can open the editor for them, but there is no audio effect.
Am I missing a step? Does this work for anyone? Is there a known incompatibility?
I would appreciate any/all information or experiences.