Some time ago, I was editing my puzzle and suddenly saw the vote count move up. By the time I competed the edit, the vote count was back, which surprised me enough to accidentally not commit my edit.
Then I saw this in "Recent Reputation Changes":
The 3 upvotes on my answer were by 3 users. Assuming that one of those users also upvoted my question, that would make 2 votes by the same user. Is this enough to be considered "Serial Voting"? Why was it reversed against only my question rather than my answer, or even both?
At times, I have upvoted 3 or more items, without encountering this situation. The help section has no mention about this.