The reason there's a long wait to redeem sometimes is that once there's a new dataset in Stall Catchers the movies will only become available to redeem once enough people analyze each movie, so we can get the crowd answers for them. You can now track this progress with the new "tribar" feature as well (learn more about it here).
We need to complete three passes for each movie for it to become redeemable. During the first pass (analysis), all the movies are seen once by at least one catcher; second pass (validation) -- all movies get a "second opinion" by another catcher than before; to get reliable crowd answers, in most cases each movie will have to be reviewed by 3 (sometimes more) catchers -- third pass (verification). Once we reach that stage the movies will start entering the redeem stage very quickly!
Of course we realize it can be frustrating to wait for them in the future, however, we might come up with a way to have more than one dataset and/or smaller pieces of each dataset, so there are no such redeem "gaps". But for now you can at least watch the new tribar to have an idea when to expect to have movies to redeem! That will be once the bar starts filling in blue: