100 KG gold coin from Canada has a NRI 95. Does that mean someone owns one?

There are only 6 existing so if the Numista Rarity Index is 95 does this mean that someone in our midst owns an $8 million dollar coin? Or is this just an anomaly in the index? Or did someone make an error while entering their collection?

It's likely someone added it to their collection as a joke. It's highly improbable a Numista user has this coin in reality.

There are multiple unique coins owned by multiple people.
Reasons are joksters, people who for what ever reason need to see a double tick, data miners with bad programming skills ...

for a coin like this, even if 8 Numista users own it, the rarity index should still be 100. Because the mintage is 8.