After login on Spanish StackExchange site, I received the "Vote Down" privilege, but, my reputation is currently 116 and the vote-down privilege page says:
Awarded At: 125 Reputation
It is a possible bug?
That day, 20 Nov 2014, your reputation was on 116 points:
Checking your reputation activity we observe:
That is, the message:
There were no net reputation changes on this day
It shows following the logic described by Nick Craver (a Stack Exchange developer) in New reputation is too verbose: upvote/unupvote, upvote again:
We now rollup in a fairly simple way: if there are 2 of a reversible vote type, we hide that group if it's within the context of a day. We won't hide something accepted yesterday then unaccepted today for example.
Since your post has an edition, it is most likely that someone upvoted your post and then, later on, retracted the vote. Since you edited it, the vote became unlocked again and gave plenty of time to a user to retract it. That gave you some 126 reputation for a while and the system had time enough to grant your the downvoting privilege set at 125.
Your reputation was indeed over the threshold briefly (thereby triggering the message), but a voter changed their mind, reducing your reputation back below the threshold.
Note that once you receive a privilege notification message, you will not receive a second message for the same privilege, regardless of how many times your rep goes over the threshold again.
So all of this seems to make sense and be status-bydesign.