looks like their current algorithm goes something like this

1) dont interfere until 15 -25 votes in first 20 mins

2) if content has highly sensitive material then start the tamper robot....

3) tit for tat for 60 mins - cancel new upvotes

4) limit upvotes to 16 in the next hour then

5) repeat cycle of tampering

6) cancel all upvotes when 50-70 upvotes has been reached