I've already asked about a similar situation, but this time the figures involved seem to be quite exaggerated: on my reputation page the following item appears:
-4360 Serial upvoting reversed
The other time the nullified votes were 63, this time 436, which is what a user can vote in eleven days.
I can understand that StackExchange doesn't want to disclose how they keep track of suspicious serial voting, but in this case something seem to have gone wrong. I see only one of the following possibilities
- a user has serially voted for 11 days without the script noticing it;
- two users have serially voted for 5 days without the script noticing it;
- more than two users have serially voted in the same time frame.
None of them seems likely. Are there other possibilities?
Note: this hasn't had any impact on my reputation, since the nullified votes have in most cases been replaced by valid votes that hadn't contributed to the reputation because of the cap. The question is general: this possible bug may have heavy impact on other user's reputation.
I'd like to add some data. My current number of answers is 1773 in 347 days, which gives an average of 5.1 answers per day. So the suspected serial voter can't vote more than 5 answers a day, which means 87 days. Assuming four serial voters that act every day, this means 22 days.
Another hypothesis is that, when a serial vote is detected, all votes from that user to the target are nullified. This is absurd.
I'm pretty sure that many users upvote almost all my answers. Does this qualify as "serial voting"? Is this the case? If it is, the algorithm is flawed.
The reputation graph is clearly wrong and surely offensive.
I didn't lose 4015 rep points on March 2 as the graph seems to imply. The new system takes care not to show lost reputation for deleted answers, while, to the contrary, in my case it shows utterly wrong data. On March 2 I indeed got 345 reputation.
I can understand that StackExchange nullifies some upvotes because of suspect serial voting (which is not my case, but it's only my opinion); I can't understand why such a big non loss of reputation is gigantically exposed for all to see, when I did nothing wrong (I have received six downvotes and have 1798 answers).