I’ve seen a couple of those pop up in high activity systems over the months recently - namely in CG systems, but also when LHS 1163 was buzzing because of BGS action against Azimuth.
Not that I’ve investigated them too closely. Mostly, you just get smaller-scale trading missions offered by the same NPC there, and I’m not much of a hauler anyway. So didn’t look into how well they pay out compared to just visiting the mission board(or what makes these pop up exactly).