Is there a reason, you think, the Charles family is living in an apartment with only a maid instead of the hill top mansion and large staff they had in ATTM?
I was thinking maybe they sold it, moved back to NY and were having an extended visit to San Francisco.
"Strange women lying in ponds distributing swords is no basis for a system of government."
-Dennis
I was a bit mixed up about that myself. This series goes to the trouble of making sure the Police Lieutenants in New York and San Francisco are played by the same actors even when the films were made years apart.
But in After the Thin Man Nick and Nora are living in a large house with a front yard (rare in San Francisco) that is shown (in rear screen projection) to have a view of the Bay Bridge and so is likely supposed to be on Telegraph Hill. Here they are living in a huge hotel suite. They give the name of the hotel to someone but I forget what it was. Like you say, are they just visiting?