I can’t seem to get Vienna Ensemble Pro’s “Audio Input” plugin, used with its corresponding Server Interface plugin (to a slave and back), to stay in sync with Cubase.
Its PDC only seems to work when routing the VEP Server Interface to “Stereo Out” (either on a instrument channel or in the instrument rack).
If I route it “within the mix” to a proper Group Channel, it’s out of sync.
The VSL engineers are quick to point out how this is not what VEP was designed for, but that doesn’t seem to stop many of us from trying. 
Anyone having luck using VEP for offloading inserts that also happen to be on Group Channels?
It seems the use-case VSL wants us to use it for is a reverb send/return notion, but I’m not sure how that even stays in PDC sync if all it can be monitored on is a “Stereo Out” that’s outside the project’s mix bus context.
UPDATE: I found a solution (mostly). Here are details of the saga: FORUMS - Vienna Symphonic Library