OS X Mountain Lion 10.8.5 Supplemental Update
Apple has released OS X Mountain Lion 10.8.5 Supplemental Update with a couple of sleep-related fixes, including a bug that could cause external drives to be ejected after your Mac goes to sleep and a problem that prevented HDMI audio from working after wake from sleep. The supplemental update also fixes an issue that prevented some applications from accessing the FaceTime HD camera on mid-2013 MacBook Air models and a bug with USB Bluetooth adapters. It’s available as a direct download from Apple’s Support Downloads Web page or via the Mac App Store. (Free update, 18.7 MB)
Apple also appear to have re-released the 10.8.5 and 10.8.5 Combo updates to include this supplemental patch: the dates on the download page are later, and the download sizes have changed.