Sidechain Stopped Working

Has anyone ever ran in to this issue? I have a project where I was using some sidechain compression. I rendered the midi out to wav’s imported them back in to the project now it seems like the sidechain isn’t working any longer. It seems to only be affecting 3rd party plugins. If I use the built in Cubase compressor the sidechain is working fine. Oddly enough with Pro-C it isn’t working (it was previously) and neither is the Vengeance Multi-band sidechain. Another interesting thing is when I try to use the VPS Transmitter plugin to send the signal to the Multi-band sidechain plugin to trigger it that way instead, that is also not working. The funny thing is it seems to work just find in other sessions.

Anyone have any ideas? I’m using the most recent version of Cubase 7.5 on the mac. The project may have been originally created on Cubase 7, I don’t remember. Thanks.