My Lock Screen Keeps Getting Stuck On Portrait.

I hope someone can help me. My lock screen on my Samsung Galaxy Tab S 10.5 (SM-T800) is getting stuck on portrait and I can't get it to move at all. I have the rotation lock set so my screen will switch from landscape to portrait , but when the screen goes to sleep and I turn it back on the lock screen will just jump on portrait and NOTHING I try will make it go back to landscape. I did a restart, no good, I turned it off and powered it back on, nothing. I then did a whole factory data reset, set it up as a new device, backed up my data and hoped for the best. It seemed to work but after a few days it started doing it AGAIN. So... I am stuck, can anyone please assist?