Plot hole: Bonnie is the anchor for the other side and feels when supernatural beings die. How come she didn't know Katherine wasn't dead? Did she never think it was suspicious that she never felt Katherine's body after she died?
Suggested correction: Katherine died but didn't go to the other side. So she didn't need to go through Bonnie. She went to hell to Arcadius. Bonnie is not the anchor to hell, we don't know how going to hell works.
After everyone finally realises that Elena had been possessed by her Doppelgänger Predecessor, It is actually shown that Katherine were more or less dragged away from Bonnie before she could crossover to the Otherside. So we do have some idea as to how one ends up in Hell.
Suggested correction: Katherine was a human technically when she died.
Technically, she was supernatural because she was a doppelganger, so she should've gone through Bonnie.
And even she was a traveller.
Character mistake: Steffan addresses his brother, Daemon, as "Steffan" at The Grill after Ellina talks to Steffan about the crystal that plagues Bonnie with nightmares about Emily. (00:15:06)
Suggested correction: You missed the point of the scene. They were imitating each other. Stefan was pretending to speak as Damon. Damon replies with "I don't, Damon" and then "you're really hard to imitate".
Other mistake: When Elena is taken, Bonnie asks Jeremy for help. She says she needs his blood to cast a location spell to find Elena. But it doesn't make sense. Earlier it was revealed that Elena is adopted, so she and Jeremy don't share the same bloodline and cast could not work well.
Suggested correction: Elena was adopted by her uncle. Grayson Gilbert (her adoptive father) is John Gilbert's (her biological father) brother. Jeremy (Grayson's son) is actually her cousin, and related by blood.
Factual error: During the flash back of 1912, one of the characters pulls an American note out for Damon, and it had the date 2016 or 2010 on. (00:13:00)
Suggested correction: That's not the date. The blue number is basically the serial number, not the date. The series date would be in too fine of print to see in the shot of the bill.
Continuity mistake: Giuseppe Salvatore wasn't buried at the family crypt because it hadn't been built yet. But Lily Salvatore was buried at the crypt despite dying before Giuseppe.
Suggested correction: She faked her death.
