Depends on how they actually update the list. While that jump might seem a little odd if they adjust it in real time, if it is instead updated periodically it makes more sense. If they only update the rankings every week or so, then that shift might line up to the Aigis activity from the Dragon Slayer event.
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And also, currently there is no event going on in PPS. Even the collaboration thing at the moment is to play OI to get some bonus in PPS, and not about playing PPS itself.