I don’t know what could be happening…
Looking at the code, you can see it has to do with a non-admin user:
Although that doens’t make much sense when running a command-line upgrade. My guess is that some of the jobs getting executed, at some point try to do some web redirect or something not originally meant for the command line.
And it’s probably a false-positive. If you could find out which one of those checks is calling the sugar_die, you could probably just comment the sugar_die to ensure the installer continues. After a successful upgrade, uncomment it.
Good luck