"You suspect..."
"I suspect he's not the real Yun Shen!" Maybe there is such a person, but he's definitely not the man he saw today. Moreover, after hearing that he has a large scar on his chest from Wanwan, Su Chaoyang had a general guess about this man's identity.
Shentu Yun, Yun Shen.
These two names, which seem completely unrelated, are just reversed and one character removed.
And those scars, they were likely from burns or explosive wounds when he escaped from Jiugu Town on the Myanmar border over a year ago.
He clearly remembered that when the local police couldn't close in, they directly bombed the place. Even if Shentu Yun could miraculously survive, it would be impossible for him not to be injured.
A person's appearance can change, the voice can change, but some daily habits are not easy to change. If he replaced the real "Yun Shen", then no matter how perfect it is, there will be flaws exposed.