The memorial was working fine.
It's just that the warning signs/buoys that should have been there weren't at the boundaries of the effect any more.
this is exactly why Voyager had to stay in the Delta Quadrant, they couldn't trust automation to get 'er done.
EMH: Even if we do shut down the transmitter I'm afraid your memories of the massacre are permanent.
TUVOK: But we'll prevent this from happening to other passing ships.
NEELIX: If we do that, all record of what happened here would be lost.
CHAKOTAY: The monument will still be here.
NEELIX: But that doesn't really tell the story. Someone put a lot of time and care into building that transmitter. We can't just deactivate it. We don't have the right!
KIM: Did they have the right to force us to relive all that?
NEELIX: They wanted others to know what it was like in the hopes that nothing like it would happen again.
CHAKOTAY: Why should anyone have to experience an atrocity they didn't commit?
NEELIX: Because that's how you learn not to make the same mistake. If we destroy the evidence, we're no better than Saavdra.
PARIS: Maybe he had a point.
KIM: It wasn't our fault!
TUVOK: Given the danger involved, it's only logical
NEELIX: This isn't about logic, it's about remembering.
CHAKOTAY: Some things are best forgotten.
JANEWAY: Not this. I stood by once before and did nothing. Not again.
JANEWAY: I watched while Saavdra vaporised the bodies.
PARIS: No offence but, those were other peoples' memories.
JANEWAY: The obelisk at Khitomer? The fields of Gettysburg? Those are other peoples' memories too, but we don't honour them any less. The eighty two colonists who died here, they deserve their memorial.
JANEWAY: We're not going to shut down the transmitter. Is that clear? Is that clear?
TUVOK: Are you suggesting we leave it intact?
JANEWAY: I'm suggesting that we repair it. Recharge the power cells. I want that monument to function properly for another three hundred years. We'll place a warning buoy in orbit. Anyone who enters this system will know what to expect. Dismissed.
She also charged the batteries?
If the memorial was designed with a finite life expectancy, rather than a regenerative power-supply, like solar or geothermal, it's possible that the designers decided that this wasn't going to be an open ended project and it was in the process of being decommissioned when Voyager...
Now I'm thinking about that ^%$# Goldilocks rifling through the three bears house like she was some sort of entitled (*&^ princess.