Plot hole: This was the first episode of the series and we see that the rangers are unable to figure out how to properly operate their zords; but in Origins Part 1 (which takes place prior to this) they have no issues with the zords at all.
Recognition - S1-E17
Plot hole: Bridge could have used his powers to figure out if Wootox and Sky's bodies were still switched.
Plot hole: They need at least 12 magnets to make it work, Paige collected 11. (00:21:00 - 00:22:00)
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)
Plot hole: The bad guy somehow knows what is going to happen (via the sketches) even though the events haven't happened yet, like knowing Mrs Peel was going to show up at Pool's mansion in that catsuit and hat, and that the scenes were going to play out like the sketches.
The Book of Blood: Chapter Two: The Perdi - S2-E6
Plot hole: When announcing the 14 deaths, they make a generic statement to the friends and family of everyone in the pods, without first telling the affected families directly?! There's no way this would be dealt with like that - not least as they all then seem shocked that the parents start a riot/panic about whether their children are dead or not. Anyone with half a brain cell would have seen that coming a mile off. Not to mention that later on we discover one of the parents STILL hasn't been told if his daughter's alive or not. If this was a coverup or otherwise secret they wouldn't have said anything - there's no reason to announce the deaths but not clarify who died.
The Feminum Mystique: Part 1 - S1-E5
Plot hole: If her younger sister Drusilla is sent from Paradise Island to retrieve Diana, how did she get to Washington DC or wherever, she had no way of knowing where her older sister would be.
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)
Deathfist 5: Major Crimes Unit - S2-E15
Plot hole: The whole case is solved because of astronomical coincidences, since the culprit is someone related to the actor, who is teaming up with the investigators for an entirely unrelated reason. Los Angeles is kinda too big for this sort of 'coincidence'. Moreover, had they committed the crime any other day (there was no particular reason) there would have been no connection.
Plot hole: In episode 3 Ray and a CIA agent meet a US Ambassador to Tunisia to discuss placing a Seal team in Tunisia to combat the recent wave of terrorist bombings. The Ambassador was against boots on the ground. In episode 4 when Bravo team arrives to find captured Ray, they land at an airbase in Tunisia and enter a portable type building, on the wall of said building are US Military patches such as 82nd Airborne. Did the ambassador forget America has portables there for their troops?
Plot hole: Loki states while on trial that The Avengers should be on trial for traveling through time to change the timeline. How did he know they came back through time?
Suggested correction: He recognized that there were two Tony Starks in the lobby by the smell of their colognes, and combined with all the other unusual shenanigans going on, he correctly deduced the Avengers travelled through time, though he incorrectly thought it was to prevent his ascendancy.
How exactly do you distinguish the smell of cologne as belonging to two separate people? But besides that, it's pretty wild to jump to a conclusion about time travel when it could be that someone else happens to be wearing Axe.
I'm sure he simply recognized his voice.
Plot hole: In Russia, Soldier Boy is shown heading to the airport, He wanted to get to the US and start his revenge against his team. Problem is: he has no documentation and money to take a flight. Even if he stole the money somewhere, still would be impossible to travel without the proper documents.
Plot hole: Sydney is able to surmise from the artwork (we could also say from the writing, but her rival is one step ahead of her for 2/3 of the episode and it is established that he does not know the language) the precise location of the koi in Lumbini. The map is 150 years old, but there's no way even with a big stretch of imagination to buy that they both'd be able to pinpoint with such ease and certainty its location in the basement of a random building in the bustling market center of a town, that surely changed plenty during the past century and that does not bear any special landmark.
Mondays Are for Murder - S2-E13
Plot hole: In an effort to keep Glenn's death as quiet as possible, Higgins hires a private pathologist to do an autopsy to see if there were any foreign substances or poisons in his system when he died. A few scenes later it is revealed that Glen was undergoing chemotherapy. How is it possible that the pathologist missed the cancer and the chemo treatment in his investigation? What he found was an excess of antacids.
Gakkou wa senjouda! Taiketsu Ryouma vs Ryouga - S1-E8
Plot hole: In his flashback, Ryoga emerges from the sea and faints on the beach of Okinawa. That's quite the big oversight in plot, since Ryoga, as revealed in the following episode, has a curse similar to Ranma's and he would have emerged from the sea in his animal form and not as 'himself'. (00:07:20)
Into the Mouth of Evil - S2-E23
Plot hole: While fleeing the guru's disciples through a narrow side street, Jackie gets cut off by the van driven by Dr. Jamba and associates, stun-sprayed in the face, and then loaded into the van. But with three brutish-looking guys being so close to their quarry, the real crooks can take the time for dragging Jackie around to the back door instead of loading him through the side doors?
Hiren Lake Legend Murder Case: File 3 - S1-E6
Plot hole: The plan of the killer relies on a couple of pretty strong coincidences, such as the fact that they wouldn't realise their common link (he knows nothing about what happened on the cruise, so he couldn't know that they all wouldn't realise they have met before) and the fact that the boat is discovered at the perfect time for him to commit murder (on someone who wasn't part of the trip, but is willing to join him).
The Night of the Raven - S2-E3
Plot hole: Antoinette is making miniature clothes for the soon-to-be shrunken West, but when West drinks the antidote to make him normal-sized, he is wearing the same clothes which would have been shredded as he grew back to normal size.