Thank you for your replies.
 
I agree with grumbelweed, if it worked in X2 it should work in X3.

 
Noel Borthwick:
"Can you check something?  In X3 we respect the interleave reported by VST3 mono plugins so if you try and toggle the track interleave to stereo and have a mono only plugin as the first in the chain, the UI will NOT toggle to stereo since it will force it to mono. Can you report back what happens when you have only pod farm in the bin and try and set the track interleave to stereo?"
 
Thank you for your reply Noel. I hope I understand this corectly. I set Pod Farm back to its original settings like in X2.
I have a mono signal and only Pod Farm in the fx bin. When I have the interleave in mono, I have the same processed signal in both channels and when I have the interleave in stereo I have the processed signal in the left channel and a bypassed signal in the right channel.

As Craig said there appears to be some sort of interop problem when its being set to stereo mode by SONAR.
X3 has new VST code to specifically handle stereo and mono plugins and now uses effGetInputProperties and the "speaker arrangement" to determine what the plugin supports. In earlier versions this wasn't the case and as a result plugins with multiple *mono* inputs weren't handled properly. 
 
Saying "if it worked in X2 it should work in X3" is not necessarily such a binary decision. We have to support a vast number of plugin configurations and a tiny change can trigger different interpretations of the VST API to cause incompatibilities.  In this case the change is definitely for the better since several other plugins that did NOT work in X2 now work well in X3.
Anyway until I look into this specific plugin I don't know whether the issue is on our end or not. Either way we'll figure something out and I will contact Line6 if necessary.

Thanks Noel.
 
As it is now, we have a solution that seems to work fine.

 
Thanks Noel.
 
I understand what you're saying about how the new method works, and to me that agrees with that section of the manual I inserted.
 
The weird thing here is how the signal is being split. As Johannes first pointed out, it's not like a stereo effect is being added to a mono track - the plug-in is somehow splitting the signal into two (which are panned left and right) but only processing the left channel.
 
However, as per the manual, setting the track's interleave to mono pulls everything back to the centre.
 
 

Noel Borthwick [Cakewalk]
As Craig said there appears to be some sort of interop problem when its being set to stereo mode by SONAR.
X3 has new VST code to specifically handle stereo and mono plugins and now uses effGetInputProperties and the "speaker arrangement" to determine what the plugin supports. In earlier versions this wasn't the case and as a result plugins with multiple *mono* inputs weren't handled properly. 
 
Saying "if it worked in X2 it should work in X3" is not necessarily such a binary decision. We have to support a vast number of plugin configurations and a tiny change can trigger different interpretations of the VST API to cause incompatibilities.  In this case the change is definitely for the better since several other plugins that did NOT work in X2 now work well in X3.
Anyway until I look into this specific plugin I don't know whether the issue is on our end or not. Either way we'll figure something out and I will contact Line6 if necessary.

Thanks. Apologies if there was a hint of attitude but it is never nice when an update to your DAW messes with your primary guitar plugin.
The solution to the problem is simple but obviously not an expected thing to have to do when Pod Farm has worked in at least two previous iterations of Sonar.
Hopefully you and Line 6 will come to a deal .
 
Grum.
 

I have the same issue using Pod Farm. I get the processed signal only in the left channel and a bypassed  signal in the right channel.  The work around in the Plug In Manager seems to be a good solution.
 
My question to you Johannes is how do you unlock Pod Farm? Did you download the software or are you using your hardware and plugging into your computer via USB to unlock it.
 
The reason I ask this is after reading this thread last night I decided to try and duplicate the problem. I have a Pod pro 3 that unlocks Pod Farm when it is plugged in. After checking out the issue I decided to check the Pod Drivers in the preference section under edit. The Pod 3 is not my main audio interface. I use the VS-100 as the main interface.
 
I unchecked all the vs-100 drivers in the driver section (ASIO) I tried to check the ASIO drivers for the Pod. It would not allow me to do this. Even after hitting apply. I switched to WDM and it used the wave profiler. I saw the pod and I could select it. I switched back to ASIO. It saw the VS-100 and the Pod 3 pro. I still could not check the Pod unit and use it as an audio interface instead of the VS-100.
 
I then switched off the VS-100. I was then able to select the Pod as an audio interface. I switched off the Pod and I got the blue screen of death. Major crash dump.
 
This is the first crash I ever got using the Sonar X series. This is also the first one I got using windows 7. It seems I can plugin the Pod to unlock Pod Farm but when the VS-100 is plugged in I cannot use the Pod as an audio interface using ASIO drivers without unplugging the VS-100.
 
I wonder if there is a conflict between the Pod 3 drivers and the vst plugs. This is an X3 issue. This did not happen in Sonar 2. I know the limits of ASIO and I am not trying to use two devices at once. I am simply trying to switch from one device to another. This is really no big deal. I can work around it. I just thought it was worth mentioning here.
 
 

Thank you for the thread. I also have this problem and wrote to Cakewalk on October the 1st with some pictures attached to make it clear and understandable, but I didn't get any answer yet.

I also discovered that if you add some plugins behind the Pod Farm Plugin in the FX bin (in my case the RevolutionZ 32bit) and deactivate it comes out processed anyway on the left and right side. That is also a bit strange. If I add TH2 behind it does not work: On the left you hear processed and on the right it is clean.
docs.google.com/file/d/0B6CudRGVxDVsUjMwUHhKTV8xcWc/edit?usp=sharing

Hi Marcus, I have a Line 6 USB soundcard, I guess it works like a dongle.

I don't have X3 yet.  My projects are full of PodFarm plugins (hundreds of PODFarm tracks across all projects).  All the tracks with PODFarm in them are stereo.  But all the source wave forms are in mono - I record unprocessed guitar signal in mono and PODFarm converts to stereo.  Will I have to change settings on every instance of PodFarm or will my old projects play fine?