I have 8 in the review notification but when I go to that page the list have zero
Why appear that 8 there?
The review counter shows all reviews in the system, including ones that are no longer available to you. This is a sad and confusing state of affairs, but unfortunately, we can't customize the topbar count per user for technical reasons right now.
We're working on a better way to show off that there's new work to be done in /review, although I don't have an ETA right now.
Definitely a bug. I have noticed that my label for "reputation changes" is not always accurate. I could get an upvote and it will display +11 instead of +10, or show less, when I haven't had any downvotes.
Your "8" should have been updated as soon as you enter the review panel, so, for some reason, some of those labels are not telling the truth.
I wonder if there is a better way to report bugs than the tag "bug" in the "meta" section.
Update Nov. 18 2014 Definitely a bug.
Not long ago I updated a quite a few of the tags that still had no excerpt nor body, and I saw that number next to my review tab grow each time I submitted new changes. So, for some reason, is saying that there are items to review, but that you can't review them (either yo have no permission, like reviewing your own changes on tags or edits, or you already have, and they are waiting for the approval of other users).
In any case, is telling us that there are items pending of review when we can't do anything about them, so I think this mechanism should not inform that there are new review task that need your attention when there are none you can actually act upon.