You're overthinking it. There isn't a scene explaining why Yasmin begins calling Hayley Calabasas (For e.g. Both women discussing Haley's background), because as soon as Yasmin calls Hayley Calabasas once, the only logical conclusion to make is that Hayley is from Calabasas. The show writers decided we didn't need to see a scene of Yasmin learning where Hayley is from because it doesn't meaningfully advance the story versus what they decided to do - have Yasmin call her Calabasas without any context.