Was there another Datsun/Nissan car that used the same door latch as the 1980 280ZX? I've replaced the original on a friend's car because the cam that rotates around the strike post would not engage. As a result, the door won't stay closed. The replacement bought on Ebay barely lasted a week. I think the same thing happened with this one. I came across a YouTube video where someone had the same problem. It looks as if these things have a tendency to fail the same way. Whatever makes the cam stay in position when the closes seems to break.
I'm hoping there were other cars that used the exact same design because sources for 1980 280ZX latches is pretty limited.