Alternately, Fei could wind up running into Harmony, instead.  Maybe she could catch sigh of her at the start of her conversation with Golden Morning Radiance, and get curious?  The petitioner is both strangely-dressed and was outright bowing to the Modron, after all.  If she didn't get to hear any of the conversation, would Fei be the type to quietly follow after them, out of curiosity?