Here are some images at night I have same configuration with black and white option selected, before most of the times they were dogs and cats now they are persons, I want the system to alert when a person enter my house and don't be alerted by the dogs walking around.Field of view, lighting, and camera settings play a big part of this as well.
Some people try to do too much with a field of view because it works in the movies.
Some screenshots of your camera views with the mis-identification can help us troubleshoot your issues, along with screenshots of your settings.
And then as someone else mentioned, sometimes one will get the occasional mis-identification.