I had some time to look through the logs you posted. I cannot speak exactly as to why the error occurs but I have some thoughts:
- Nikon SDK support for this camera has not changed since March 17, 2016 so it's likely not out of date driver files in SGPro
- SGPro is throwing the exception when we try to set the camera's shutter speed. This error should no longer crash the application (but does not fix your issue either)
- I believe the camera is rejecting the request to set shutter speed because you might have bracketing turned on in the camera.