I had the same probUntil they update or make it more clear on the guide on how to trigger that event, I think Imma just give it a rest.
I tried talking to her with a mood of 100 all day and I got no trigger or nothing.
Idk if maybe I mest up somewhere or maybe my save file if bugged but at the moment, I have zero clue why the Pink note doesn't pop up. Unless you know the Save Editor trigger number to make it happen by chance? Cause Im out of options
the solution i found was to invite them both for 3p and the next day the notice board had the post.
it seems that the two need to meet at least once for the event to start. or for it to be triggered.