I don't really know if this counts but a year or 2 ago, when Telly had the baby duck, when he was dressed up like a duck, you could hear clicking noises made by the puppet's fake beak when his mouth moved.
Aslo, not really a blooper, but an inconsistancy... in the Letter of the Day delivery service episode from season35 (the one with Seth Green) a few of the letters came connected (PQRS was on a wheel of fortune and another set of letters was in a hanging mobile). Considering that each letter is supposed to come one day for 26 days, how can that happen if the letters are on a connected product. Unless they are pieces and need to be assembled.
Aslo, not really a blooper, but an inconsistancy... in the Letter of the Day delivery service episode from season35 (the one with Seth Green) a few of the letters came connected (PQRS was on a wheel of fortune and another set of letters was in a hanging mobile). Considering that each letter is supposed to come one day for 26 days, how can that happen if the letters are on a connected product. Unless they are pieces and need to be assembled.