Rachel works on the Popsicle stick log cabin as Urkel walks in the door, but when he comes in its suddenly sitting in the middle of the table.
When Mother Winslow remarks on what a well-rounded child Urkel is, Judy can be seen picking up her glass. It then cuts to a longer shot and the glass is still on the table and she is not even reaching for it.
During the toast to the children's mid-term scores, the shadow of a camera or crew person passes along the lower left corner of the screen.