Microsoft has updated the following KB article:
Task sequence fails in Configuration Manager if software updates require multiple restarts
If a Configuration Manager task sequence that uses the “Install Software Updates” step installs a software update that triggers multiple restarts after the task sequence successfully runs the Install Software Updates task, the task sequence can fail and generate the following error message:
Task Sequence environment not found
NOTE: This KB applies to both ConfigMgr 2007 and 2012.