Lock screen not turning off unless I do it manually (5.1.1)

I am not sure if this is a bug with 5.1.1 or not. I tried searched before coming here to post, but I haven't come across a solution yet.

Anyways, my phone doesn't have power saver on, smart stay is off, and I have my security set to fingerprint unlock.

To the issue at hand - My screen doesn't automatically time out if I press the home button or the power button to turn on my screen. In order for the screen to turn off, I have to manually press the power button. Otherwise, the screen just stays on and drains my battery. This wouldn't be too much of an issue if my butt didn't always press the home button while the phone was my pocket.

I'd really hate to factory reset or flash another rom, as I just finished installing all of my apps and whatnot after a phone replacement. However if that is the only option to fix this problem, then I'm okay with doing so.

Thanks ahead of time for reading!