This came up on reddit recently [1] and it turns out that many people are connected to Magnus through the same few accounts that look like they've cheated - accounts that beat GMs and then around the same date lose to players rated less than 1000. Can't really blame the author though, it's hard to filter out the cheaters from the dataset.
[1] https://www.reddit.com/r/chess/comments/uq4bys/i_analysed_li...