Didn't Belisario and NCIS part ways several years ago, at least creatively? I think he still get a producer credit, but not longer has any creative/management input into the show - could be wrong.
ncis LA is separate from NCIS by name alone which legally separates him from CBS. The way it works in Hollywood is, if you sell a pilot episode then the series, you as the creator for example, are bound legally to the network. And the rights are also subject to which party was able to hold on that property.
I, myself, have seen contestants in person, on the “Amazing Race’ offices, sign 4 inch thick documents which essentially, makes CBS own you and your life.