I did observe a confusing behaviour after patching a SQL Server 2012 to Service Pack 2. Some of the SSIS jobs running on that server started to fail with the message Unexpected Termination while most of the other jobs just worked as before.
Unexpected Termination can have multiple causes and if you search for that error in the internet you can find a bunch of different reasons and solutions. But non of them worked and to make the situation worse the jobs running on other servers without the Service Pack still worked. So I started looking into the known issues of the Service Pack and luckily I found this link: http://support.microsoft.com/kb/2991528
The error did not exactly match the entry I could find in the Event Viewer but all failing jobs used DT_TEXT or DT_NTEXT. I decided to risk installing the Cumulative Update (http://support.microsoft.com/kb/2983175) containing the fix. After this, the jobs started to work just fine. So in the end the solution was extremely simple.
This is just one possible solution for the Unexpected Termination error but if you experience this error after installing Service Pack 2 you should definitely check if this is also your problem.