I may be wrong, but if you click on YRtk-Main > Stats you should see:
Learning cards: 21
Relearning cards: 21
Since you have a review limit of 50, you have now:
0 new cards (because of this)
21 relearning cards + 29 review cards = 50 (your review limit)
21 learning cards (because of this
There have been recent changes in how Anki counts interday learning cards, and (again, I may be wrong, since I am not sufficiently familiar with this aspect of the program) the manual / FAQ may need an update