That old apostate 'love bombing'......please.
Oh, I said it is genuine in a way. It can be from the heart. They genuinely miss you and genuinely want you to abandon all else and come back, but might think it's too pushy to say all that so they hope just the "We miss you" part is sufficient.
Love bombing is an attempt to influence a person by demonstrations of attention and affection. With already close people, it can further be defined as an intense atmosphere of affection and adoration designed to disarm an individual's natural guardedness. You can't be mad at them if they are going out of their way to show love. There's no reason it cannot be from people who really care about you. But see if they, now that they saw you, call to invite you to that lunch.