He's not worried about the auction house.
Cyan Leaf Auction House indeed has a certain level of credibility. He's just worried that the blue-robed cultivator might reveal his matters to other Foundation Establishment cultivators, which could attract them, and that'd be unpredictable.
And that's exactly why he was boasting about his worth in front of that blue-robed cultivator earlier.
The aim was to make this person wary and scared of him.
Perhaps this tactic indeed worked, or maybe the blue-robed cultivator was just a decent person. In any case, Ji Yuan didn't notice anyone following him even after many twists and turns.
He successfully returned to Du Wanyi's home.
Not long after the auction ended, it was unlikely for Du Wanyi to return so quickly; thus, Ji Yuan took the opportunity to examine his gains.
Especially that Tier Two Spirit Beast Bag.
He took it out and held it in his hand.
