In today's version of the crash, I had two parties active (let's call them A and B). Party A was at level 9 and party B at 10, so I went to party A and used a cake so I could work on levelling it. While my Sim was still in party A, I attempted to return to party B so I could give stickers to more Sims there. Crash, kick, can't re-attend Party B because it says I've attended 2/2. I'm able to return to party A, however.
So, this makes me wonder if going from party A to party B is one of the triggers for this bug, something to do with the levels of parties, using cake, or a combination. As it possibly continues to happen, I'll try to observe further what conditions were maybe a factor.
I'm so tired of missing out on earned gems thanks to this bug ☹️