Hmm... Well, I replayed the entire game before uploading the last patch, so it's likely not a bug. After Mao leaves Lianna at the inn's door, you just have to walk back to her room upstairs. You don't have to talk to the inn's receptionist, just walk up the stairs.
(In a previous version paying the 10C for the heal teleported you inside her room, but recently I made so the screen just fades to black for a moment and you stay in the same place. This way players wouldn't get the false impression this is the intended way to get to Lianna's room and pay 10C every time without need)