I guess it was maybe part of some agreement between Haixing and Dixing: that the Envoy could operate in Haixing but his powers would be constrained by the token? You'd think it would have come up when Shen Wei's powers start being affected by healing Yunlan's sight and they have their whole kitchen fight...

Damn, now I want to include this in fic. I also recall Zhu Jiu taunting Shen Wei about how Zhu Jiu's powers aren't restrained by the token, or am I mistaken?