I kinda feel this just happens because of the lag and it's probably not a "real" new bug per se... I've seen it happen and I felt it was actually beneficial to me because events are too short for my taste anyways. With all the bs sims are doing with walking to sit down somewhere and walk back again before they can start a social interaction or trying to find a place to put the empty glass/plate from their hand takes so much time in socialisation that it's hard to actually build relationships during events because it's so hard to get them to do what you'd want.. :/