guix system roll-back doesn't roll setuid-programs back
(address . firstname.lastname@example.org)
"setuid-programs-service" extend the activation script which isn't loaded when rolling-back.
A difference between "reconfigure" and "switch-generation" (of which "roll-back" is just an useful alias) is that the former load the activation script (guix scripts system reconfigure switch-system-program) after switching the profile's symlinks and before installing the bootloader while the latter install the bootloader (guix scripts system switch-to-system-generation) then switch the symlinks (guix profiles switch-to-generation). Fixing that could be done by loading the activation script after switching profiles, as "reconfigure" does.
I guess that loading the activation script again, on a already running running system, can have side effect but it shouldn't be an issue as it's already done by "reconfigure".