Ghost Bride / Gerald v.s. Jamie O. - S5-E21
Corrected entry: The boys get locked in the cemetery by Helga so she can prank and scare them. Problem here is surely cemeteries lock up by a certain time, so it would've been locked before they arrived.
New Bully on the Block / Phoebe Breaks a Leg - S5-E5
Corrected entry: After Phoebe puts hinges on her cast and Helga and Phoebe are in the library. After Phoebe gets away from Helga and hides within the library shelves, she opens her cast and starts scratching her leg. When Arnold sees Phoebe he says to her, " I just saw you open and close your cast." Yet Phoebe never closes her cast.
Correction: He was just trying to say her cast couldn't be real and was also thinking of the fact that if she could snap the cast open she can snap it shut too. Any human in real life might say "open and close" when all they saw was the cast getting opened.
Corrected entry: The first time Arnold tries it, he says five, but Rhonda actually makes six moves; the second time, Arnold says three, but Rhonda counts off four.
Correction: That's a mistake she made as a character. Not a movie mistake.
Parents Day - S5-E6
Corrected entry: In the first scene where she's shown, Harold's mother is a brunette, but after that she has her normal brownish hair color.
Correction: This entry seems somewhat silly, as brunette means brown hair.
Correction: Not all cemeteries open and close at the same time.
That is very true. It should also be noted that not all cemeteries have overnight security or padlocked gates. So even if the cemetery was closed, the kids could still get in if this was a cemetery that isn't heavily surveilled.