There is another error with the timeline and how this matches up with Lizzie and Josie's ages. Lizzie tells Josie that they made the ascendant with Bonnie when they were five, this event takes place in It's Been a Hell of a Ride, which takes place in late February, 2018. However Lizzie and Josie were born March 15, 2014, making them around 3 years 11 months old.
Sheriff Mac hands Alaric a restraining order filed against him by Rupert Vardemus. The order states his age as 46, however later in the episode it is shown that he was born in 1976 via the criminal record that Mac pulled on Alaric. This puts his age at 52 given the timeline is at 2028 in this episode.
This is also a continuity error, as Alaric is actually only 50 given his death on November 5 or 6, 2010 in The Departed and subsequent resurrection on May 2, 2012 in Home.
On the same criminal record document, it also states that Alaric's place of birth is North Carolina. This, however, is false. In History Repeating, Alaric states that his family immigrated to Texas in 1755, though he was born and raised in Boston.
Alaric's case file, containing two continuity errors.
Josie has had Penelope Park's journal underneath her bed, of which she says she's "been listening to [the] tiny little rat claws for months". Penelope gave her the journal earlier in the year, in late March. Despite listening to the scribbles for over six months, since it's now September, she only flipped back a couple of pages to find Landon's song about Hope — this is likely a blooper considering Penelope gave all the students pens to record what's written with them in the journal.
Josie brings one of Esther's grimoires with her to Rousseau's when she meets the Mikaelson witch — Freya. Despite handling her mother's many grimoires she makes no mention of why an otherwise random witch has her mother's spellbook. Moreover, she has used the same grimoire, or the spells are contained in her own, in One Wrong Turn On Bourbon, yet there is no indication why Josie had the grimoire.
In I'll Tell You a Story, Lizzie is reading the grimoire upside-down, though the page on the left is the same page from when shown in Alone with Everybody. Despite this, in That's Nothing I Had to Remember, Josie is also reading the grimoire upside-down and the page on the right is different than the previous two occurrences.
While upside-down, the left page of the grimoire is repeated twice when Josie flips to the next page.
Davina goes through Esther's grimoire to find a spell.
Freya's Grimoire contains a copy of two pages from Esther's grimoire
Lizzie's reading the same grimoire years later.
Josie flipping through the same grimoire — yet the opposite page is different from when Lizzie had it.
Around 1585–1590, settlers of the Roanoke Colony of North Carolina were terrorized by the vampire, Sebastian. His powerful witch lover, Cassandra, summoned a Croatoan to root out the lies of the Puritan hypocrites and desiccated Sebastian — in the attempt to protect him. The Croatoan, however, killed Cassandra (and destroyed the colony) and Sebastian remained desiccated for over four centuries. Sebastian was desiccated in North Carolina, yet he was found underneath the Salvatore Boarding School for the Young & Gifted in Virginia and was awoke when MG and Kaleb spilled rancid blood from the Traveler's Blood Fountain.
Despite the error in location, which isn't explained by being moved (since the colony that knew of his existence was completely destroyed) — being in Mystic Falls would have resulted in his death in May of 2012 given Markos and the Travelers' magic purification spell that stripped away vampirism and other forms of impure magic. Even being buried underground, this would still occur as when the spell was originally cast, Stefan and Elena both began to suffer the effects of the spell while in the underground tunnels underneath Mystic Falls in Promised Land.
Sebastian buried under the Salvatore Boarding House/School
Sebastian changes the tire of Lizzie Saltzman's car when she gets a flat. However, due to being desiccated for over five-hundred years, Sebastian wouldn't know how to change a tire, as he has had little interaction with cars before.
Sebastian knows how to change a tire after centuries of desiccation
Sebastian reveals in That's Nothing I Had to Remember that he was desiccated during the time of the Roanoke colony circa. 1585 — 1590. However, Dorian remarks in this episode that Sebastian has been desiccated for 483 years. As the timeline is currently 2028, he would've been desiccated around 1545.
There is a timeline discrepancy of around 2 months with the flashbacks and the actual events that occurred.
Alyssa Chang remarks that Lizzie is the first girl Sebastian has been with since 1509; however, he was desiccated c. 1585 — 1590 when he was in a relationship with Cassandra, therefore she has gotten the date wrong.
It is, however, possible that Olivia Liang meant to say 1590, and nobody realized during filming. This would line up with the timeline and Sebastian's desiccation around 1585 — 1590.
This also clashes with Dorian's statement in the previous episode that places Sebastian's desiccation around 1545.
The celestial event that was used to create Kai's 2018 Prison World was previously unknown. In It's Been a Hell of a Ride, all Bonnie claimed was that there was no eclipse to bail him out this time. There is, however, a discrepancy about what celestial event was used.
Diego states that he was banished to the 2018 Prison World "where it's always the same day and every night a full moon.
Kai told Josie that he actually didn't know what the celestial event was despite being trapped there for over 10 years. While this was more than likely to keep her from knowing what the event was, Kai used a Meteor Shower in his attempt to leave the Prison World with Josie's fake Bennett blood. While the meteors were visible in the night sky, there was no full moon, despite Diego's claims.
Diego's claim and newfound transformation control cannot be discounted and the most logical explanation to explain this is that there was both a full moon and a meteor shower on the same night.
Lizzie unknowingly consumed Sebastian's vampire blood in Kai Parker Screwed Us. After her car accident, she has several cuts and gashes, one of which requires removal and surgery. Despite having vampire blood in her system, her wounds did not heal.
One can reason that when she siphoned Sebastian, desiccating and killing him, she could have also siphoned the magic within the vampire blood; however, that is not addressed.
"Dad, I drank vampire blood." -Lizzie, covered in cuts and bleeding.
Josie reveals that performing the Merge at 22 is a guideline and not a strict condition of performing the ritual itself. This in of itself is not a continuity error, as Josette originally explained in Fade Into You that "In our coven's tradition, after their 22nd birthday, the twins merge their strength." However, in previous Merges, celestial events were required; such as the rare solar eclipse and a Mercury-Venus conjunction. When Lizzie and Josie performed the Merge Ritual on their 17th birthday, there was no mention of any celestial event. This, however, can be explained by canon, though has not been confirmed.
As siphoners, they completed the Merge Ritual by previously siphoning or obtaining magic before the start of the ritual. Lizzie siphoned MG's vampirism and Josie was filled with dark magic from the mora miserium. Siphoners, since they're born without magic, cannot channel celestial events. One explanation could be that for a Merge between Gemini siphoner twins, a celestial event is not needed or cannot be used because of this limitation.
If true, then at least one witch would have to compete in the Merge with a siphoner in order to use a celestial event, such as Luke and Josette did with Kai.
Spells that "require" celestial events to perform can be circumvented by using an equally powerful source of magic. This was exemplified when Josie questioned Kai if the mora miserium could be strong enough to power the ascendant without a celestial event to escape the Prison World. Kai only replied with a coy "maybe" but she then demonstrated that this was true when she freed herself and the others from the 2018 Prison World. While not having a source of Bennett blood, given the above, she could not use the celestial event that was used to first create the Prison World.
During the fight scene between Hope and Josie, it can be clearly seen that a stunt-double is standing in for Kaylee Bryant. The double is Athena Akers.
It is unknown why a stunt-double would be used, given there is no dangerous acting on Bryant's behalf, with Josie only walking around the ring.
Disguised as Hope, Lizzie talks with the wolf pack at the Salvatore Boarding School for the Young & Gifted. She tells the wolves that after the funeral is planned, they can go out into the woods and run under the stars. Werewolves, however, are unable to turn at will unless it is a full moon, therefore only Hope would be able to turn at will.
It is possible that some of the werewolves were hybrids, however this was not stated.