I got a "-10 Serial voting was reversed" on the Buddhism community - a community that the only post I made was a question in 2014. The last reputation I got from that question was in 2016.
Does serial voting tracking work on reputation that happened at least 5 years ago?
EDIT: While Non-serial voting corrected can be an answer, it doesn't confirm what happened and doesn't explain why it's happening on reputation earned 5 years ago. But it does answer some of my questions, so I'm editing them out.