Child's Play - S4-E8
Continuity mistake: When Eugene is playing with the ball on a stick it changes from being predominately purple to blue and red just before he pulls the string off. The cup size changes too. (00:11:05)
Gift Horse - S4-E5
Continuity mistake: After Iola gives Mama the tissue box, Mama goes inside and drops the tissue box and the tissue paper on the coffee table. The positions of both these things (and another knick-knack that was already on the table) change between shots.