Read that article again, it doesn't say filming has begun, it says filming might begin in Vancouver. It's not shooting yet. Still in start up phase as far as I know. Script has not been approved or locked down. That article is not new.
"....Alien 5 is underway and might film in Vancouver....."
".....Even though it has not been confirmed yet, reports suggest that filming for the movie will take place in Vancouver..."
It's a load of vague BS, I'm afraid, don't read too much into it. I don't think they have a script yet.