I think I have tracked down the issue, or at least how to navigate around it. I was using Audio Creator to create a one off audio grab I described above. I began thinking about it and my thoughts are that I should be able to use my preferred audio device for whatever I deem necessary for the task at hand. Armed with that conviction, I set about trying to do just that -whatever I was trying to do.
If you allow windows to monitor the Octa-Capture's main outputs, you need to make sure you disable this feature before going back to Sonar. By doing this, I was able to get the driver to change the sample rate.
As to the sample rate change mid project, the only thing I have found that could have done this lies in the area of the windows sound device properties under the advanced tab. There, under default format the 2 channel, 16 bit, 48K (DVD Quality) was selected.
Could this setting have been enabled on the Octa-Capture as well? And if so, could it have overridden the default settings in Sonar for new projects?
At the end of the day, maybe the problem was a PICNIC error and I just forgot that I made the change at some point. Who knows. Regardless of how the issue was introduced, I have found a satisfactory resolution and want to extend my thanks to you guys for responding to my initial query.
Let me know if I need to further elaborate on this solution.
Cheers!