I wrote this response and was proud to get 200+ upvotes:
At some point, additional upvotes stop adding reputation, which is fine. (false!) However, today, someone apparently decided to retract one of the upvotes, and I was surprised to find myself docked 10 reputation points.
It seems to work like this:
upvote +10 reputation upvote +10 reputation ... upvote +0 reputation vote retraction -10 reputation upvote +0 reputation downvote -10 reputation upvote +0 reputation
For a highly voted post, an upvote adds no reputation but a downvote or an upvote followed by a retraction will dock 10 points. In theory, with enough up and down votes, one could even lose more reputation than the post had originally gained ... Why should this be so? This seems like it can't be intentional.