When Tim and Jill are helping Brad with his math homework, in one shot Brad's notebook is open, and in the other, it's closed.
In the opening scene, the woodpecker wakes Tim up in the middle of the night. Woodpeckers are not nocturnal. They roost at night.
Towards the end of episode #2.18, "Bye, Bye Birdie", Tim drops to the ground in the back yard while trying to avoid the helicopter. When Tim gets up, you can see the grass (carpet) move and wrinkle up.
Tim wears a black helmet outside. Several studio lights are reflected in the helmet.
Al says that eight and a half times four and a third is thirty-six and four-fifths; the actual product is thirty-six and five-sixths.