This happened a couple times in the past and I wasn't sure why, but now I have some solid reproduction steps for you to follow. It happens with all DCAM plugins in the bundle. I don't recall this happening with the 32 bit versions, so it is probably just a 64 bit bug. If someone wants to confirm that, that would be great.
When using any of the DCAM products on OSX 10.6.8 in a Cubase 6.5 (64-bit), if I export a track (to permanently render fx to a track for instance), it will cause the DCAM plug-ins to become unresponsive until I close and re-open the session. I usually solo a track and perform an offline bounce of it and have Cubase re-import the track. At this point, when I attempt to playback the session, the plugins are unresponsive. I know it is unresponsive to MIDI events on the track. I don't know if it is unresponsive to 'live MIDI' from a connected keyboard.
- Load a Cubase 64 bit session with above software
- Load up a few tracks with DCAM plugins
- Load a separate track with other plugins or audio
- Solo the non-DCAM track and do an export. Tell Cubase to re-import the export into a new audio track
- When the export is complete, note that the DCAM plugins don't respond to the MIDI events on their tracks