This one’s primarily an issue for players who are raiding in Combat spec at the moment.
A few folks have taken to various forums (e.g., here) since Patch 5.4 went live to note some oddness with combo points in Combat spec. I’m still a little bit unclear on the details, and I haven’t seen anything official from Blizzard on it. But there appears to be an odd interaction happening between Anticipation and the new Ruthlessness passive for Combat rogues, especially those with the Tier 15 four-piece raid set bonus.
The gist: If you have Anticipation stacks and hit a finisher, Ruthlessness is guaranteed to proc a combo point. That combo point is generated on your target. But you still have Anticipation stacks — which are on *you*, not your target. It takes a moment before those Anticipation stacks get “transferred” from you over to your target, where they become regular combo points.
I don’t know how long it takes for that transfer to happen. I also don’t know how much server lag can play into it, or how much of it is a display issue vs. an actual gameplay issue. But the end result appears to be that, especially for Combat rogues who have Adrenaline Rush active (and thus have their global cooldown on many abilities reduced by .2 seconds) — and ESPECIALLY-especially for Combat rogues who have AdRush + Shadow Blades active and still have their Tier 15 four-piece bonus (which reduces the cooldown by another .3 seconds) — it appears possible for them to have a total of 10 combo points available (5 regular, 5 Anticipation), try to hit Eviscerate twice in a row, and end up hitting a 5-CP Evisc followed half a second later by an unintended 1-CP Evisc.
So, that can be a little frustrating. :)
If you’ve got any additional info, evidence, video examples, etc., please comment here or over on the Combat EJ thread (where the most discussion around the problem is happening right now); hopefully Blizzfolk are watching and can address the issue if it’s actively causing the sorts of problems it appears to be causing.