Sc got this award when shooting was going on. Maybe sm had already wished her on sets but these fans can't think logically.
Also they have each other's phone numbers...and likely private IG handles too, and WhatsApp, and the ability to send DMs. What makes these people think they haven't spoken in private since they left the show? Just bc you don't post something publicly doesn't mean you haven't spoken to someone who is your colleague/friend in private.