Phoebe vs Max: The Sequel - S3-E1
Continuity mistake: Throughout the episode Max's watch is on his on his left hand, except in one shot at the high school.
Other mistake: In a previous episode, it says that Phoebe and Max's ice breath can't touch or it'll freeze the whole city. In this episode they blow their ice breath at each other twice.
Phoebe vs Max: The Sequel - S3-E1
Factual error: All the orange juice that sends Max flying through the air couldn't possibly be strong enough to do so. We already know that Max is pretty strong (The Girl with the Dragon Snafu).
Are You Afraid of the Park? - S3-E5
Other mistake: When Nora lasers Phoebe her clothes have holes in them but Nora lasers Billy all the time and his clothes are fine.
Phoebe vs Max: The Sequel - S3-E1
Audio problem: When Hank gives Chloe that heavy piece of metal, she falls to the ground and you hear the it hit the ground. But we hear the sound effect a split second late.