I leave my computer running and so overnight TeXStackExchange kept running and I ended up with a reputation of 17,925. When I updated my view of the site to get the latest questions my reputation was decreased to 17,910. Why was this and how can I find out who caused the change? I would like to be able to ask for the reason.
The answer can be found on the Reputation tab of your profile, which contains all your historical reputation changes:
Another user unaccepted an answer of yours which was previously accepted. In that case, you lose the 15 reputation you gained when the answer was accepted, as indicated in the FAQ on Meta Stack Exchange:
- One of your accepted answers loses accepted status (i.e. unaccepted): −15