So it turns out I was wrong about what I thought was causing the issue, but now I'm 99% sure I have isolated the problem. It has something to do with charging the phone via USB, or more specifically connecting the device to a computer system. After attaching the phone and letting the display time out or sit for a little (screen may still rotate while attached) it seems to "fix" the screen in the vertical orientation. I have no idea why though...
I have been using the wall charger for about a week now and the screen rotate has been working fine. My phone hasn't been rebooted in over a week and I've been using all of my apps regularly. Before it wouldn't even last a day without the screen rotate becoming locked so I'm going to say the source of the problem is USB connection to PC. I can't say if this is a desktop OS, mobile OS, or USB specific issue but it seems like for whatever reason connecting the phone to my computer causes the bug.