Don't Bug the Mosquitoes - S2-E12
Other mistake: The 4 band members, all their equipment, months worth of food supplies, I am assuming medical supplies, change of clothes and other sundry items all magically fit into a small two seat helicopter.
Other mistake: Although Diane Murphy played "Annabelle", she is listed in the closing credits as having played "Diane". (00:25:00)
Other mistake: As Virgil prepares to clear the wreckage of the tower from the rescue area using the Firefly, Scott tells him that he will go over to Thunderbird 2 to prepare the Mole for tunneling. The Tower Controller then says to Scott, "I've got a fast car ready for you outside" without moving his lips.
Come Back, Little Googie - S1-E25
Other mistake: When Eddie's naughty little friend goes to shake hands with Herman they insert a quick close up of a hand buzzer in his hand, only it's obviously an adult's wrinkly hand.
Other mistake: As Fester goes to shoot Gomez, his aim strays upward to about a 45 to 50° angle. Not enough to shoot the support chain on the light that is directly above him, and hits him on the head.