Is regeneration sleep?
The argument can be made that Drones are "Awake" during the regeneration process.
At least their bodies remain awake while their minds go somewhere else.
Where does Seven's mind go now that Unimatrix Zero has been demolished?
The Borg must have had out of body work details that they should have gotten annoyed that her psyche never turned up for the swing shift while her body was regenerating... If her mind had no where to go to, because she is not Borg, and it stayed in her body, then Seven would have been awake rather than seemingly asleep while her mind was empty.
ICHEB: You took these scans of me when I left the Collective. By your own estimation I emerged from my maturation chamber before I was fully assimilated. As a result my physiology is less dependent on my implants.
EMH: They still regulate many of your vital functions.
ICHEB: What about my age? I'm younger, so it should be easier for my body to adapt to the loss.
EMH: You're obviously too young to understand the risks involved.
ICHEB: I understand the risks perfectly. If we continue to do nothing, Seven will die.
EMH: And if we proceed with your idea, you could both die!
ICHEB: According to my research, there's an eighty six point nine percent chance that Seven's implants will adapt to my node.
ICHEB: Point nine.
EMH: What about you. Without a cortical node how will you regulate your implants?
ICHEB: You should be able to compensate with genetic resequencing. This isn't suicide, Doctor. I believe it can work. All I ask is that you consider it.
Seven could wander into Unimatrix Zero despite that her subspace radio antenna had been disabled, so really what ever tech had her mind subconsciously connected to and driving offsite/remote Borg mechanisms during regeneration was still active till at least the end of season 6 that she could have been acting as a widget or an engine fulfilling any number of Borg Agendas the whole time little orphan Annie was on board Voyager.
She was only half free.