I burnt through my 30+x votes very quickly today, leading to the notice (in blue upon reaching the limit, in red upon trying to vote thereafter):
You've reached your daily vote limit; vote again in 11 hours.
But then I was cruising over some answers, and I was able to cast a vote on an answer. (In case it helps, I know which answer it is, but I won't disclose it immediately.)
Again, the notice was displayed (this time with "vote again in 1 hour") in blue, and the vote was counted; it also appears in my profile (the number of votes cast has gone up by one). After this one successful vote, I got the red notice again, and my votes don't get counted.
Is there any explanation for this behaviour?