Elsa can't help but mention it to her therapist. They don't have any words of wisdom to offer; in fact, it's one of the less helpful sessions Elsa's had. But she also knows it's mostly her fault.
"I hope she doesn't invite anyone over for Christmas," she laughs, offhand towards the end of the session. The therapist looks at her for a moment before asking, eyebrows furrowed, why not.
Elsa goes to answer before pausing. Why not?
There's no reason for it – no reason to even suspect Anna would. So why mention it?