I have found that if I upvote an answer, it gets upvoted, but if I downvote I receive a message that the vote is hidden until I have sufficient reputation points.
Here's an example from an answer on Academia - on which I have 101 reputation points.
If I upvote:
It simply gets upvoted - isn't that nice!
The trouble is if I downvote an answer, I get a message saying my vote is hidden until I have 125 reputation points:
And here is an example of a question on Network Engineering, on which I have 113 reputation points:
So either this is a straightforward network-wide bug, or this is a Stack Exchange policy to hide downvotes from users with less than 125 reputation points - in which case perhaps the wording of the message is ambiguous?