There's a lot of users on Twitter also documenting this problem to @Sprint, @SprintCare and @HTC. One response from a SprintCare rep suggested resetting by dialing ##72786#>Menu>Reset. I did this last night, so we'll see if ItsOn starts draining my battery today. So far so good, 1 hour off the charger and it's not showing up. However, I had initially restarted my phone when this happened over the past week and ItsOn wasn't draining my battery for a day or so...then it would come back on. So I'm gonna wait a few days.
According to SprintCare on their community forums, their engineering department is looking into a fix (hopefully). If you can, I'd suggest reporting that you're experiencing the same issue on the link I posted above...or tweet them.