I think I am close to narrowing the problems down. My field unit has not reset all week. Ever since I stopped powering the nano Router from the usb port of the OP3. I was able to reproduce it on my bench as well without any load on it other than the nano router. Once it gets to the point where it resets every time you try to access the log, the only way to fix it is to factory reset the controller.
With that said, since I have pulled the nano router off from the OP this has not happened. Which is good news, I can work with this. I do suspect that this behavior is triggered under certain conditions and it seems to revolve around writing to the sd card and having a power source running on the controller. I have not troubleshooted as to whether its any device powered by the controller from the usb port or not at this point.
Hopefully this will help others and I am not sure if this can be resolved with a firmware update or not. But I believe it can be avoided.