Kiseki no fukkatsu! Yuyo no cosmo - S1-E5
Plot hole: Miho is watching the match at home, and it is day - the kids in the previous episode also entered the Dome when it was afternoon, and a clock at their place when they watched the first of Seiya's fights showed it was 4 pm. Yet she takes a taxi for the arena when it's dark outside.
Plot hole: When Connie uses the wish machine to make Malloy small again, she instead wished for Ethel's breasts to get significantly bigger. However, in the next scene Ethel's breasts are back to her regular size. The plot shows that the wish doesn't wear off, and someone else would have needed to wish for Ethel's breast to get smaller but no one did.
Der Kampf gegen den Drachen - S1-E3
Plot hole: Shiryu states that the Dragon Cloth, which has been 'for eons' under the waterfall (let's just say it's an exaggeration) is harder than diamond and invulnerable to any attack. In the original manga and anime series, Pegasus uses a sudden dodge during a daring grapple to get Shiryu to strike his own shield with the glove of the armor, shattering both ("invincible sword meets invincible shield") and causing him to fight barechested. In this remake, this whole part does not happen, so when Seiya wins the fight with a heart punch like in the other versions, he does it when Shiryu has his heart still covered by the thick breastplate of the armor, making the whole "Shiryu's armor is impervious to any hit and much stronger than any other Cloth" plot point completely moot.
Suggested correction: It is only said that the "Dragon Shield" is unbreakable.
No, says much more than that. "That might be true for other armors, but the Dragon Armor is special. Nothing can get past my shield. It's unbeatable. The day my Cosmo forced the waters of the Lushan to flow upwards, it revealed the Dragon Armor. Battered for eons by the falling water, the Armor had grown harder and more radiant than a diamond. My Armor is the hardest substance known to man. No matter how fast or hard you strike, you've lost, Seiya." He parried the blow with the shield and so that deserves a special mention, but they keep mentioning the armor as having intrinsic properties, and he is wearing the armor when he is struck by Seiya, which guards his heart. In the original anime and the manga he was armorless after Seiya wrecked it, in here it's intact. It makes no sense, which is why I categorize it as a plot hole and not just as Character error: it's not that maybe he's wrong about the armor, it's the whole situation that now is flawed reprising the original with key differences.
The Hong Kong Kowloon Treasure Murder Case File 4 - S1-E4
Plot hole: Miyuki has been peacefully waiting for over a day at a stranger's house because she was told that the whole Hong Kong was under lockdown and her friends were in another location. That cover story (which would have been exposed if only she looked out of the window, people were NOT in lockdown) does not explain at all the kidnapping in the clothing stall or why she didn't have her phone or talk to Hajime at any point. She'd have to be braindead not to question even slightly what was happening.
Plot hole: Why would Danger Mouse go on the roller coaster at the end without seeing Greenback go on it first? Greenback went first in the ghost train. It also doesn't make sense that Danger Mouse would go on it when Penfold pretty much tells him flat out that it IS a trap.
Hone made aishite? Akane koi o fukuzatsu kossetsu - S1-E5
Plot hole: Dr. Tofu is able to tell that Ranma was hit by a softball (he says something about the marks like he actually sees them), but Ranma's wound is still covered by the bandage, that he'll remove in the next episode. This is linked to a larger mistake in the following episode. (00:19:55)
The Muh-Muh-Muh-Murder - S1-E25
Plot hole: Daffy isn't able to escape Porky's house until he gets the keys, but later it is revealed that the reason he couldn't get out was because he was too weak to open the door. If that was the case, the keys shouldn't have been able to help him get out.
A Scooby-Doo Valentine - S3-E3
Plot hole: It's never explained how JC Chasez and the Hollywood extras impersonating the gang gained the super strength they possessed to do things like ripping car roofs open or holding up the Mystery Machine.
Plot hole: Ezra escapes from the Ghost crew through the ship's ducts. When the ship comes under attack from TIE fighters, he eventually falls out and into the nose gun turret. However, that turret is directly connected to the cockpit. There is no duct where he fell for him to fall out of.
Plot hole: During Ryder's report, as Bruce and company watch it on TV, the camera suddenly zooms in on Joker standing on a catwalk above Ryder, and none of the crew, especially not the camera man who caught the villain, makes a comment about this. They may have thought the Joker (or rather an impersonator) was perhaps a surprise gag in the show, but since this is supposed to be a serious documentary report, it is still strange that they wouldn't point it out.
Farewell My Beloved Witch - S1-E3
Plot hole: Lupin was captured by chance, and he did not plan for that, nor he seemed to have previous knowledge of Stern's appearance, but he escapes regardless using a Mission Impossible-like perfect mask of him. He also somehow kept his own blazer, tie and shoes underneath the uniform and boots he stole and wore. (00:16:00)
The Wedding of Iron Man - S1-E13
Plot hole: When Mandarin is concluding that Tony Stark and Iron Man are one and the same, he is watching video footage of when he had Tony Stark captive, and Tony first constructed the Iron Man armor and used a dummy that looked like himself in order to fool Mandarin into thinking that Iron Man was rescuing Tony Stark from captivity. If Mandarin had video footage of Tony Stark in that room where he organized his own rescue, then he also would have had footage of Tony Stark constructing the dummy of himself in the first place, and thus would have known Stark was Iron Man from the get go. (00:13:06)
The New Kid - S2-E7
Plot hole: In the season two episode 'The New Kid,' Daria and Jane are discussing The New Kid in gym class when a girl takes a nasty spill from a trampoline. Later, Daria and The New Kid are heard remarking about photos taken of that particular fall despite there having been no photographers present.