I think I may have figured out what is happening here.... I think the SuperSU app and SU binary are getting messed up when the SU app updates from the market. This would explain why it will sometimes break over night.
I tried flashing SU in recovery a bunch of times and it doesn't restore root but if I re-flash my ROM, I usually get root back. I think the difference is that all the SU components are getting reset to default when I re-flash the ROM but when I flash SU, it is just applying it on top of the existing root/su.
I was checking some settings and I found a work around that seems to restore root without having to re-flash my ROM....
Settings > More > Application Manager > ALL > SuperSU > Uninstall updates
Then, I reboot the phone and root is restored when it comes back up.
I have tested this by updating and uninstalling the updates a few times and I lost root every time I updated and it came back every time I uninstalled the updates and rebooted.
I disabled auto update in the market for SuperSU, so hopefully this issue stops happening. If not, at least I have an easy fix.
Thanks to all for the suggestions & help!
Let me know if this fix helps anyone else!
Primary Line: Samsung Note 2 (T-Mobile)
Work Line: HTC Inspire 4G (AT&T)
Tabs: Samsung Galaxy 10.1 & iPad 2
I'm old school, used to work for T-Mobile back in the day & my first Android was the HTC G1.