Okay, here is my point: When Fang Yuan refined Fixed Immortal Travel, it should have been a massive 'boom' for the entire Southern Border and, consequently, for all Immortals. Many Rank 6 Immortals—if not most—cannot even dream of obtaining an Immortal Gu, and they make up the vast majority of the Immortal population.
The fact that a mortal could refine one—and not just any Gu, but a legendary one—should have been a 'hot topic' in Treasure Yellow Heaven. So, how is it that He Feng Yang didn't immediately know that Fang Yuan didn't belong to any organization? How is it that Hei Cheng didn't know who Fang Yuan was the moment he saw him use Fixed Immortal Travel?
How did such an improbable news story—a mortal refining a legendary Immortal Gu under such... impossible conditions—not become a recurring theme in Treasure Yellow Heaven? We know how gossipy Immortals can be, especially those at Rank 6. Is this a plot hole or a massive plot convenience?