According to a video I watched, Raditz is supposed to spawn after you kill "Reginean Saiba Unit Elite" but he didn't spawn for me. I don't know if this is a common or a rare bug. If this is a rare bug, the only thing that comes to mind is that I nuked the whole mob pack in one hit.
I tried going back to see if I have missed something but nothing turned up. The quest on the side "Blew attack" is not green which makes me believe that's the reason Raditz didn't spawn.
Here's proof that Raditz didn't spawn:
edit: this is a repost because the old post was in the wrong forum section, old post is deleted