It very well could be. The point of the Task Manager is to stop applications from running in the background for too long. Typically, the best apps to put in this catagory for the auto-end feature would be games that use data.
I recommend removing all applications from the auto-end tab and restarting the phone. If it continues to misbehave in the way you described it could be a faulty manufacturing.
A little note: Android phones don't require app-ending applications or any sort of user action to end applications. This is done automatically by the operating system as memory starts to become limited. Once at this point, the phone will automatically end processes in order of which ones use more memory (RAM). The Electrify is nice for this instance because when an application runs for more than 5 minutes without any sort of user interaction the phone will give a pop-up notification stating the application running is not being used and will ask if you want to close it.