Character mistake: The officers count the inmates and say there's 10 missing. There are indeed 10 inmates hiding in the pool. However, Pennsatucky and Chang had escaped the prison. The officers counted Linda as an inmate, who had been hiding in Litchfield the whole season, and wasn't on the list. That would make it 11 people missing, not 10.
Factual error: Tiffany asks a guard where he would go if he could travel back in time. He says he would return to 1999 to attend a Judas Priest concert he missed. He says he wasn't able to get close to Rob Halford. The problem is Rob Halford was not the lead singer of Judas Priest in 1999. Tim 'Ripper' Owens was.
Character mistake: At the end of the episode when Maria is framed for the prison panty business and told to expect an additional 3-5 years on her sentence she cries saying that her daughter Pepa will be in kindergarten by the time she gets out. However in season 2 episode 12 Maria tells Piper that she still has 6 years left on her sentence. This means that even without the extended sentence her baby would have been well past kindergarten age by the time she was released, so taking the extra 3-5 years into account, Pepa could be almost finished in elementary school by the time her mother got out of prison.
Visible crew/equipment: When Flores discovers her cell phone is missing from the hole in the wall she goes nuts, slams the stall door and kicks it in. After she is taken away there's a closeup of the stall and we can see the metal spring that was duct-taped to the bottom of the wall inside.
Continuity mistake: When the officer is taking Gloria to D-Block because she had a "friend in high places," and she asked where he was taking her, when she's walking down the hall towards D-Block, she's only carrying a small bundle of belongings, but then once it cuts to her entering D-Block, she's now carrying all of her stuff in a much larger bundle. (00:44:00)
Continuity mistake: Larry and Cal are cooking hot dogs over an open fire. Larry starts out with a straight stick, Cal with a curved stick. Larry puts his hotdog on the curved stick, then has the straight stick as he puts it over the fire. The swap happens again and Larry ends the scene with the curved stick. Also, the tip of the straight stick swaps from a sharp point to a dull point. (00:40:30 - 00:41:50)
Continuity mistake: When Red and Flores are texting Piscatella to come into the prison from Humps' phone, in one of the texts, Humps says "Thx" and Piscatella texts "Np". The time Red and Flores send is 4:59 and the text is sent from iMessage. When Piscatella checks his phone the time is 4:56, the messages were sent by the opposite people, and it's an Android phone, incompatible with iMessage. (00:53:03)
Continuity mistake: During episode 6-3, it is established that all inmates at the Ohio prison facility are required to have their hair cut in order to prevent the spreading of lice. Later on in the series, it is revealed that almost all of the inmates that were not moved to Litchfield Max after the riot were sent to Ohio. Despite that, several of the inmates formerly from Litchfield were shown still having long hair in scenes that took place in the Ohio facility, and Maritza's hair was long when she first appeared at the nightclub while she was on parole. While it is possible that the policy may have been rescinded between the events of seasons six and seven (which would explain why Alex's hair was still long when Piper visited her), that does not explain the other characters that were immediately transferred to Ohio still having their hair long during subsequent appearances.