[epochwolf]

This happens if you have full disk encryption enabled. If the laptop goes into hibernation, the disk is no longer mounted. So you need to enter your password to mount the drive which then drops you into the lock screen to enter your password again.

Ideally, the computer should be able to know you just woke the computer from hibernation and skip the second lock screen but I don't think the systems are integrated enough to do that right now. :)