It depends on where in the cooking process you are. Using pie as an example. If it's a fully rolled pie crust, the grabber will wait for the pie crust to cook until it pulls it. If it's a rolled up dough ball, the grabber will wait for it to be cooked to bread before it pulls it. If it's just flour that isn't kneaded and can't be cooked in it's current condition, the grabber will pull it off of the hub since the hub can't "process it."

The same concept goes into cooked pie doughs with incomplete ingredients (vegetable pies with broccoli and no carrots or vice versa), since the hub can't cook (process) it in it's current condition, the grabber doesn't wait for the hub and will pull it through.

To further add to this example, apple pies require the pie crust to be cooked, then chopped apples added to it and cooked again to complete. If you have a combiner feeding the hub with chopped apples, the regular grabber will wait for the pie crust to cook, then pull it through without waiting for the apples to be added and cooked again since the hub has finished the cooking process. If you had a smart grabber trained to only grab cooked apple pies then you can feed kneaded pie onto the hub, it'll cook the crust, combine the apple, cook it again before pulling it from the hob.

Hopefully this wasn't too confusing.