I have the same problem although I think when you see the submissions vote go up it's someone else since they get voted on a lot more than individual comments. For me it's both in chrome and firefox (in Win 7) so I don't think it's the browsers faulth and I noticed it for the first time maybe a 15-30 days ago. I'm guessing one of three things are happening:
1) We banned from voting as the moderators doesn't seem to tell people when they moderate.
2) pg is running an experiment.
3) It's a bug.
I agree that there needs to be a place to report malfunctions. It would also be nice to know when a moderator takes action against you.