We recently reported about one specific bug in Family Fun Stuff, and as posted in a BBS thread there are many others as well (although missing custom content is easily fixed by enabling it and restarting the game). Nevertheless Maxis has fixed two main problems with a new patch. Family Fun Stuff content will no longer disappear from the game after usage. The other problem that's been solved is an object error when both the helicopter and the nanny car arrived at the same time. Even though these are just two changes, the patch takes 26 Mb of disk space for the download. You can get it from the update page.