MetalTeK
You don't see how a user forum and interaction with support staff offers support to users?   Okay.

I do not believe that is what I wrote. Keep in mind the only staff participation in the previous thread was from Focusrite.
 
good luck
sc

Try uninstall drivers/reboot/reinstall drivers/reboot/reset interface.
Also delete AUD.INI (Google for details).
Disable interface in windows control panel-sounds.

MetalTeK
I read in another post that ASIO drivers are Stereo only, is this true? 
And could that have anything to do with it?
 

No, it is not correct.  but the way they report to Windows and ultimately Sonar is not intuitive for some people.
 
L ASIO Focusrite 1/2
R ASIO Focusrite 1/2
Stereo ASIO Focusrite 1/2
 
is something similar to what you will see.  if you choose Stereo, you will record a stereo track.  if you choose "L" you'll choose INPUT 1.  If you choose "R" you'll choose INPUT 2.

Beagle
No, it is not correct.  but the way they report to Windows and ultimately Sonar is not intuitive for some people.
 
L ASIO Focusrite 1/2
R ASIO Focusrite 1/2
Stereo ASIO Focusrite 1/2
 
is something similar to what you will see.  if you choose Stereo, you will record a stereo track.  if you choose "L" you'll choose INPUT 1.  If you choose "R" you'll choose INPUT 2.

^^^^^^^^
 
I have an 18i6 so similar in nature to what you're using, and this is what you should see.  For example, I leave my guitar cable plugged into the first input and a mic cable in the second, and in SONAR I choose either the L or R options depending on which input I want (but never stereo in my case since they're entirely different signals).
 

Is the OP still here - is the issue resolved?

Okay, sorry I didn't get back sooner.  
Uhhh, I don't know why, but as far as I can tell,  it appears to be the track template I was using.
I have always used the "normal" template to start a song because I use audio and midi tracks.
I started a new project and used the "16 track audio" template and everything seems to be fine, regardless of what my input is set to, I get a true mono recording now in one channel, which is what I wanted.

Much thanks to everyone!