From what I understand, this is how they always act after they come upon you with cargo they want. They ask you to drop some of it. If you do, they leave you alone, and you can pick it back up again.I collected it, moved on to the next rock. Pirate comes back. Comes right over (still in red on the radar), just sort of sits there, then goes again. Never came back. It was weird.
When I was mining in the bubble and there were pirates, I was in my Cutter so I just blew them up and never actually tried that, but I've heard it more than once.
Out here, there are no pirates, so I don't have to even think about it