It happened to me too. Even though I am a new player (less than a week in), I quickly took a liking to this game, but I must say that since yesterday, I am quite turned off by this issue. Now for two days in a row, successful (lvl 10 and many many other sims in attendance) parties I had attended and contributed to the progression got erased from my party list when I wanted to return (following my closure of the app in response to the party not loading and being left with the same « the sims mobile » white screen). Upon reopening the app, I was then left with a list containing only one active party while saying I had attended two. The first instance of this issue happened yesterday in the first hours that my daily party « allowance » was set back to zero. The second happened just a few hours ago, within the first hour of my party count being set to zero again. To this time, I can only speak for the first instance of this bug as to its consequence on my earned reward: like most people here, I received nothing for the party that I « lost ».
I am new to this forum and though I have read (briefly) the posting «how-to » pages, I envision the possibility of my not respecting certain instructions, and I would like to appologise in advance.