But the user leaves no comments, nor do they leave the upvote there long enough to garner the attention of the person they're upvoting. The up/unvotes were literally within the same 30 second timespan, so if that's their intention then I'm not sure it's working.

In fact, it appears the @cheetah bot has this user on their blacklist.
Okay.... I thin this problem is solved. It appears this person is either just a bot or someone doing a very poor job of what they think is gaming the system.