For those of you having trouble with a rooted kernel (perhaps causing reboots while calling), you can install a stock ROM to fix the issues. These are also deodexed versions of stock firmware so you can do cool stuff like install Xposed installer.
These stock ROMs come with root and also you can install over your stock firmware without any wipe but please do make a backup ROM just in case!
T-Mobile Galaxy Note 5 SM-N920T Stock ROMs
Download Galaxy Note 5 SM-N920T T-Mobile Stock ROM Android 5.1.1 OI5 [latest] – Link – Credits