Odd Couples - S2-E1
Audio problem: The delivery man's (pushing the plasma television) lips are not moving at the top of the video.
French 101 - S2-E2
Continuity mistake: In their attempt to make Esteban feel better, when London stands at the doorway shouting at Maddie outside, the colorful shopping bags on London's arm change their order in the close-up.
Free Tippy - S2-E5
Continuity mistake: When Carey hands Cody and Zack the pet rocks, her handbag goes from her shoulder to her arm, back up to her shoulder between shots.
Revealing mistake: This is very obvious. When Zack comes back with the bike and gives it to Cody, and it breaks apart, you can definitely see at one point the string/wire that holds it together.
Continuity mistake: In the scene where they are having the finals, the things on the desk change a few times.
Other mistake: When London is reading her book to the little children, the small girl wearing pink with a ribbon in her hair is miming what London is saying, just before London actually says it.
Plot hole: The whole episode is based on false facts. Cody was getting an A in woodwork and Zack was failing in all his classes the previous year at school (according to their report cards in Ep "Smarter and Smarter"). So Cody knows a lot more about woodwork than Zack and should be able to make a clock, never mind a birdhouse, and Zack should not be able to make a clock.
Continuity mistake: When Zack trips on the slick floor, his red backpack ends up behind Cody, but in shots facing the kitchen the backpack is across the room, near the kitchen cart.
Continuity mistake: When one of the older twins in the wheelchair throws the apple and his twin catches it, we see that nobody is standing on the stairs in front of the main entrance. Though in the previous and following shots Moseby is actually standing on the second step.
Neither a Borrower Nor a Speller Bee - S2-E12
Continuity mistake: When Maddie is painting the apartment, London is reading the article about Porsche's charity work, and the actual newspaper changes between shots.
Revealing mistake: After Arwin scores the winning spare, Esteban and Mr Moseby lift him onto their shoulders. When they drop him there is obviously a large pad to catch him as you can see his legs stick up in the air between Maddie and Esteban. It is even more noticeable as he bounces up and down on the pad a bit.
Revealing mistake: When Arwin gets both the seven and the ten bowling pins causing Team Tipton to win, if you look very closely at the close up of when he hits them, you can see that someone is controlling the pin with something to make it hit the other one, because right before he hits it, you can see the pin jerk a little before anything touches it. Pretty obvious.
The Suite Smell of Excess - S2-E15
Revealing mistake: When Arwin tries to use the P.U., when the door is closed, you can plainly see a reflection of Cole Sprouse waiting offstage.
Revealing mistake: When Arwin admits he cheated, on one of Arwin's lines, the guy behind Mom (the guy with the clipboard) silently mouths along with that line.
Continuity mistake: Right at the start, when Zack is hanging on the tree branch, the long sneaker laces are in front of Cody's shoulder, but when Zack falls, they're gone, though the sneakers have not moved.
Audio problem: When Cody orders the Number 8, someone says, "We got a Number 8". But no one's mouth moves.
Revealing mistake: The whole time London is on Maddie's back and is dropped off, the stunt doubles' faces are noticeable.
Volley Dad - S2-E24
Continuity mistake: Towards the end (during the closing credits) when London comes and find Maddie sleeping on the bench, they talk for a while and you can see Maddie has her bag beside her but when they leave the bag is still on the bench.
Revealing mistake: At the end of the episode, when Moseby and the rest do the dance number, London falls from the stairs onto the floor at the bottom, near the candy counter, when she hits it, you can see the corner of the blue crash mat come up.
Visible crew/equipment: In London's suite, when Arwin opens the door to the porch where the hawk is nesting, the reflection of a crewmember wearing a white shirt is visible on the door's glass panes.
Answer: Keep in mind, Muriel wasn't very popular. So the writers/directors must have thought it'd be a good idea to let go of the character. No one seems to be complaining.