As mentioned in the comments on this question about one bug with the new reopen reviews...
I saw this happen a couple days in a row on Serverfault but didn't get screen shots, today it happened on SciFi:
When I started reviewing, it showed a lot of questions waiting to be reviewed, but as I did a few reviews, the # waiting plumetted. What happened to the other questions?
At first there were 43 needing review:
I reviewed 2, got a message "Sorry there are no more items for you to review" and it showed 20 needing review:
I refreshed a couple times, was able to review 2 more, and then there were none: