Lord Solar was adept at the Way of the Primordial Spirit. Whenever Administrator Sun secretly manipulated this Avatar, regardless who he encountered, he would subconsciously "scan" their soul.
This beast soul of the "Dragon Body" was genuine and couldn't be flooded― it was a beast soul of the familiar Christopher. Now, as for why the symbolic three blood eyes were only two left... Perhaps when Christopher disguised himself, he didn't need to maintain this feature, he merely did it intentionally. Or perhaps, Christopher, after consuming half of the Vitality Corpse, has gained enough power to break this limit.
Administrator Sun felt the former was more likely. Being "Christopher", why would there be such an obvious flaw? If such a noticeable "sign" existed, how could he be called Christopher? This was not a common Demon Beast; it was a Divine Beast Avatar, there must be a way to bypass this loophole.