I have not investigated Dahua camera logs much. Would that leave a hint?
Not sure since it is logging in to the camera under the credentials. I will have to look and see if the log includes that kind of detail like SMD being turned on or off.
All I know is many of us have seen some wonky stuff with BI and DS - some have seen their motion zones for A and B get switched, some cameras wouldn't trigger but rollback and they would again, ONVIF triggers would quit working but rolling back and they would work again, so it isn't too far of a stretch to think that unintentionally it could be sending a command to the camera.