When homes are listed in the mls listing system, agents have the ability to check a variety of boxes on the inputting sheet. Of these, one says show complete address. This is a fairly simple clerical issue and easily corrected.
Since she's at Sotheby's, it's likely that they have a clerical person who does this for the agents.
If your agent is doing listing management herself, she goes into the My Listings section, then she goes into the edit property section, then she goes into the Remarks section, then she'll see the button that says Internet and then she'll click on the "show complete address" button.