This is a new bug that started with the latest patch. The same thing happened to me in regards to the family inventory, and I just used buydebug (wasn't a challenge file) to re-purchase the items in question.
Then, after saving the same file, when I went to play the next time, only one sim was available to control. All the other sims in the family were "greened out" on the left panel, and you could not control them. Resetting the sims did not work. But what did work was going into Edit Town and saving a copy of the family to your bin, and then moving them to another neighborhood. This is still not without consequences, as any wishes, friends, etc. will be lost. I also noticed that since my founding sim was working on her Pervasive Private Eye LTW that her progress towards fulfilling it started over. I suspect that any LTW that tracks progress that way would be reset.