Only a handful of Skype users have reported this problem over at the support forum, but what they're complaining about is pretty hair-raising. They say that, following an update in June, instant messages have repeatedly and unintentionally been forwarded to random people in their contact lists. In other words, third-parties are seeing stuff they were never meant to see, which constitutes a serious breach of privacy. Skype now tells us it's aware of the issue and is working on a fix. Here's the official response in full:
"We are aware that in rare circumstances IM's between two contacts could be sent to an unintended third contact. We are rolling out a fix for this issue in the next few days and will notify our users to download an updated version of Skype."