In the middle of vacation times at least in Sweden a new update was released that requires multiple reboots and therefor will fail an OS deployment task sequence in Configuration Manager as we seen a couple of times before. This issue is addressed i System Center 2012 Configuration Manager SP2 and R2 SP1 but if you haven’t upgraded yet then it still will cause an issue.
The update is: KB3073094
And the article that lists all the updates that requires multiple reboots is updated as well: https://support.microsoft.com/en-us/kb/2894518
Thanks for the heads-up Tim: https://twitter.com/t1mnl well spotted!