mine comes and goes for no apparent reason (I was without votes for about a month at one point).
So I've given up flagging more than once a week and voting a more than a couple of times a day. Sadly all the older HN members I talked too say the same thing.
I wonder if the site algorithm is actually favoring newer / less active members?
I've asked for that many times, but since it seems that both my flags and votes are being ignored again I won't bother any longer.