Ditto. Hadn't heard of the bug, so I spent a good bit of time trying to find some time-sensitive quest I'd missed, until I had the blinding flash of the obvious that it was a bug. Not a huge deal since it doesn't bump me down a reputation level, but still unfortunate.
As a sidenote, it'd be neat if there were some kind of system where the log told you why reputation gain/loss happened. It could just be generic templates like "Lost reputation with ______ for [completing quest|failing quest|killing] ______." Doesn't need to be super specific per-quest fluff, but having something would make it a lot less confusing when you don't immediately notice the log entry, or when there's a delay between action and the resulting change.