Plot hole: In the start of season 4 we meet Liberty's little brother, Danny. J.T. and Manny are making fun of him because he is new to the school and is starting out. If he is starting out, then he should be in the 7th grade, because it is stated in the first episode that the school changed into a 7-12. Liberty, J.T., Manny, Emma,Toby etc. are all in the 10th grade so how does it end up that Danny is a grade below Liberty?
Plot hole: Emma is getting people to sign a petition to get tampon machines in the girls' bathroom. But in the episode "Mother & Child Reunion," when Joey and Caitlin are in there, there's a tampon machine. So you can see that they took it out or just neglected the fact to support the plot of this episode.