The beads are there to moisturize the humidor walls as well as humidify the space inside the humidor. With such a small amount of air space inside the humidor and the interior walls being shielded by all of the cigars, the humidor walls will not be able to absorb moisture, and once the moisture from the initial seasoning in the humidor is absorbed into the cigars it can't get replenished from the surrounding air. If the walls can't absorb the moisture it's going to stay in the beads, and the cigars are going to suck up moisture faster than the beads can release it. Remember, we're talking about passive evaporation here.

You really need air inside the humidor for it to work properly. You shouldn't be filling it more than 3/4 or so of capacity. I suspect that unless you have 77 cigarillos in there it's stuffed pretty good.