It may be important to note that I have renovated all lots that these events spawn on. I have not yet been able to try with a new save due to limited time since the pack released.
Darby's Den @ UBrite Commons
Larry's Lagoon @ Foxbury Commons
Laurel Library @ Gibbs Hill
Pepper's Pub @ Gibbs Hill
(they will spawn in the quads if you are in the campus housing)
Drake Hall @ UBrite
Wyvern Hall @ UBrite
Darkwing House @ UBrite
For me, this is currently happening with all the University of Britechester organizations and the Brainiacs of Foxbury. I went through an entire 4 terms of university, took a 3 days sims time break to get my younger sims that were going to university to apply and age up, and came back to a broken system. My previous sim was part of the soccer team and Foxbury Spirit organizations and graduated. The sim was still listed as part of the organization after leaving university life. Two days after graduation, the previous sim was randomly woken up in the middle of the night by a secret society member and requested my sim join the secret society. My sim said yes. It is important to note my sim had not recently done the appropriate action to trigger this event to occur. My sim had done the required action at least 2 sim weeks (2 terms) before the event occurred.
I have not attempted to go to a Foxbury Spirit Squad or Bot Savants events yet from experiencing this issue. For a while (5-6 sims days), nothing was showing up for the events. After a few days, the items are now spawning, but no NPCs that are apart of the organizations are spawning. I have even gone into the University Debug menu and added sims to the organizations before the event is due to spawn, and they do not show up. I was getting LEs left and right for the events happening but the correct sequences are not triggering.
If I am at the lot before the event happens, my game either throws a LE or "crashes" my kicking me out to the Manage Worlds screen with an Error code (I have not yet captured the error code). I then have an " ! " mark above the lots that my sims were on. If I go into build mode to fix it, nothing is missing.
If I am not on the lot before it happens, I still receive a LE a the time I am supposed to get a pop up for the event.