I previously posted "TSAR-1R reverb not working in ProChannel (works in effects bin)".
 
I have just checked and find that all Softube Cakewalk SONAR ProChannel Modules do not now work in ProChannel.  Instead any module produces a tone when enabled or disables Sonar (requiring to closing the project).  Sonar Platinum is updated as are the Softube Prochannel modules.

Last time I tried Softube Prochannel modules they worked, a recent update to Softube or Sonar may have introduced a bug.

Weird. Try re-install?

Is this happening in more than one Project?  I have one Project where the side chain for Melda's MDynamicEq plugin won't work.