I have a laptop (Dell Studio 1557) that I have set to go into hibernation when the lid of the laptop is closed.
I have been annoyed for the last while that when I turn on the computer to resume from hibernate, it would immediately shutdown again, but this time in sleep mode.
Today I had a look at the power options, and saw that sleep was set to occur automatically after a number of hours, specific timing depending on whether it was being powered by the mains or battery at the time.
I have disabled automatic sleep and hibernated the computer. This time, when I resume from hibernate, the computer no longer goes into sleep mode. I would have assumed that waking from hibernate would have reset the sleep count-down, but obviously not. Perhaps this will be fixed in a patch sometime ?