In the episode "Little Sister" where Karl's sister comes to Mansbridge seeking the ghost of her brother, Malcolm clearly states that when he saw Karl he was wearing his letter jacket....but in the episode "Grave Matter" in which he sees Karl in the midst of The Chill and debating with Murdoch, the vampire has on a checked lumberjack shirt, not his letter jacket. In fact, the only time in the episode in which he IS wearing it is when he visits his gravesite. Malcolm is nowhere in evidence at that time.
Explanation 1- A minor error in which the character of Malcolm might of associated Karl with the letter jacket so in turn mentioned him to work it.
Explanation 2- The writer of the episode may have used the letter jacket in the episode because it was so apparent from when Karl had "The Chill".
In "The Bleeding Frenzy", when Merrill asks everybody what their last meal was, Drew says french fries and an egg cream, but if he was turned in the 1800's, those types of food didn't exist then.
Explanation 1- The only plausible explanation for this one is Drew ate the food then BUT used terminology from today to make the explanation easier.
Essie's hair, yes she can style it differently, but sometimes it looks lighter in some episodes and looks like it has been cut. Would Murdoch allow her to go out and get her hair styled?
Explanation 1- To be honest there seems no real explanation within the show. But in the interview with Karen Cliche who played Essie she says the hair is a strawberry blonde colour at the start because it had to be changed from black which is difficult to do. So when the hair is different later on it could be how the executive producers originally wanted the hair to be.
In the episode in which the Vampires see each of their kills they regret the most Karl is said to have killed Carmen and his best friend. But in the second to last episode with rogue Vampire Bridget, Karl says he has only killed once before and not the two we had been lead to believe.
Explanation 1- When Karl says to Bridget only one kill that could of been the only kill that has meant something to him which was Carmen, the girl he loved.
Explanation 2- It is possible that Karl never killed his best friend. Maybe he only bit his best friend and then he survived like Dillon did in the final episode after Karl had bitten her.
At the beginning of episode 2 we have the security guard Dwight talking about things whizzing across the school security camera. But on the ending credits he does not appear. Yet the mystery does not end there! If you watch the next episode, episode 3 he is included yet not in the episode.
Explanation 1- A simple technical error meaning the name was supposed to be on the end of episode two but ended up on the end of episode three.
Explanation 2- The security guard may have been in episode three as well originally but cut afterwards.
On the opening credits when all the main Vampires and Sherry have a tile with a blue tint yet Marty (Joris) does not. The only other one is Murdoch but he is just to end and only has one tile to himself.
Explanation 1- Added later on Marty could of been a late addition and was added quickly to the credits, other than that no idea!