Potentially, it should just be tied to interacting with the door or being inside the apartment after completing the fancy dinner date but there's obviously something interacting and breaking it.
We will look into it and see what's going on, in the interim you have any save files close to this where you could reload and see if trying this quest earlier fixes it?
If not, starting a new game and choosing to start from latest content will get you to this part of Leslie's quest