Double boot solved
My T999L would boot twice every time I would turn my phone on or restart it. At least it wasn't a bootloop I guess. Well after a month of searching I finally think I found a solution to this. And it also seems to have fixed the issue with Android System (UID) Asking for root. This fix was for a Note 3 experiencing the same issues. I haven't seen anyone else here Mentone this problem, but just in case, here it is.
Settings > Connections > WiFi > (menu soft button) Advanced
Uncheck 'Always Allow Scanning' (5th item down on Advanced settings page).
Go back to Home screen, long-hold power button, and select 'Restart' from the dialog box that appears.
Hopefully this will resolve the problem for you. The 'Always Allow Scanning' advanced setting under WiFi isn't really necessary and can cause boot loop issues. My Note 3 began doing this and removing the external SD card would stop the boot loop from occurring, thus leading me to assume the problem was related to the SD card is some way. This turned out to not be the case.
Sent from my GT-N8013 using xda app-developers app