I have not tried another switch and turning off the NVR because I feel it would not help me as in the end I need the NVR to record regardless.
Of course. I was only mentioning it because it was unclear if the NVR was affecting the settings on the camera. The web interface should have a way for you to see when the motion event gets created, so you could isolate the flaky behavior (or not) to just the camera alone.
If the camera works on its own satifactorily, then you could try it with the nvr again, this time watching that the same events that you see thru the web interface are repeated on the nvr.
If they are not in sync, then either the nvr does have its own motion detection*, or the communication between them is failing.
This is definitely a case where getting latest firmware can matter.
Assuming that the firmwares are up to date, I'm not sure what you would do next, as client side motion detection not a requirement of Profile S.
btw, my Dahua NVR says it only supports motion detection from Dahua cameras. Perhaps, as has been suggested, the Seetong cameras have a firmware that is Dahuan in origin, but not fully compatible.
*though I agree with others that it is unlikely to have this capability.