Other mistake: 1970: Barnabas fends off a werewolf by striking at it with his silver-headed cane. Unfortunately, the cane bounces off the resilient werewolf and hits Barnabas in the head. (Jonathan Frid reportedly had to have a few stitches afterwards.)
Other mistake: 1967: Burke mangles his line to Vicky, and instead of telling her to get off her history kick, says, "I just think you should get off that hickory stick for a while."
Other mistake: 1967: A persistent fly insists on clinging to Barnabas' forehead as he plots to kill Dr. Hoffman. He tries to ignore it, tries walking briefly out of camera range, then comes back and tries shooing it away on camera, but it keeps coming right back.
Other mistake: 1795: Reverend Trask is attempting to perform an exorcism when a (demonic?) fly aims straight for his mouth. He has to interrupt his incantation long enough to blow it away.
Other mistake: 1967: The death of Sam Evans didn't play out according to the script. That's because the cameraman accidentally knocked the teleprompter off (with a loud crash), causing the dying "Sam" to sit up and yell "Where is it?!" "Maggie" ad libbed, "Never mind, Pop. It's going to be OK." Poor Sam then had to expire without delivering any poignant last words to his grieving daughter.
Other mistake: 1968: The now-vampire Angelique kneels beside Barnabas' chair to tell him he belongs to her now. When she tries to get up, her long white gown catches on something, causing her to muff her next line a bit as she gives the fabric an annoyed tug to free it.
Other mistake: 1969: David blunders his line to Cousin Amy: "Don't feel too bad, Amy. I don't like to feel my relatives, err, I don't like to see my relatives."
Other mistake: 1966: Standing over the doctor's microscope, Burke blows his line to Woodward: "When you examine it under the microphone, it doesn't show any mystery at all."
Other mistake: 1897: Barnabas forgets his verbal 'shopping list' of five potion ingredients as he delivers it to a servant. He says, "Now go into town and collect Magda's herbs and, uh, herbs and, well whatever else it is she needs."
Other mistake: 1897: Valerie Collins is supposed to praising Collinwood. But instead, she gushes, "Hollywood. I never imagined I'd see it."
Suggested correction: I listened to this carefully and it is incorrect. She does, in fact, say Collinwood. The enunciation is just a bit muddled.
Still sounds like "Hollywood" to me. But the correct name, in any case, is "Collinwood," not "Collonwood."
Other mistake: 1840 Parallel Time: Julia Collins suffers from a bad case of tangle-tongue syndrome when she says, "Don't you think that I would like to help Bramwell gill the coast of Brutus Collins?"
Other mistake: 1968: When David and Amy discover Quentin's sealed room, the youthful performers forget to stop on cue and skip to lines from their next scene. The view cuts to Liz and Roger in the drawing room, but the voices of David and Amy excitedly continue from the set next door.
Other mistake: In episode 367, there is a continuity glitch. Vicki Winters travels back in time from 1967 to 1795 as the result of a 1967 seance gone awry. Vicki is disoriented and confused by her surroundings and is made to lie down and rest in a bed. There, a granny square blanket is placed over her - the exact same one as seen in earlier 1967 episodes at Sam Evans' house, draped over his sofa; the green granny squares around the perimeter of the blanket are a dead giveaway that it's the same blanket. Either there was a mistake made in that they hoped nobody would notice that this same blanket appears over and over again in the series (it appears again in the series in unlikely places in episodes even after #367, as well), or it's a mistake to try to pass it off that this 170-year-old blanket was somehow still in perfect condition in the future, in 1967, at Sam Evans' place. Either way, it's a mistake.
Other mistake: 1795: A black-and-white cat, supposedly the transformed Joshua Collins, was completely uncooperative in every scene he was in. He always started out on a bed or a chair, but got up and left every time, usually forcing the camera to pull in so that the actors could pretend the cat was still there.