Messaging Panam for a date is broken for me. It has worked several times, but twice after missions (maybe due to having to wait during missions? one was the main mission with the floats in japantown and one was the first string of missions in phantom liberty) the text message for inviting is just gone. First time i fixed it by inviting before the the mission, which started the "hangout-mission" consisting of waiting a few days. Now it has happened again with the starting mission of Phantom liberty, which is a fair few hours to replay... And I am not even sure it would fix it this time.