Continuity mistake: From the outside of the house, you can see the staircase and door are to the far left of the house. But from inside the house, you have a fireplace and the staircase to the right of the door. So you know it's not the same house they use in the show.
Continuity mistake: In season 1 Hobbie was 13 and in season 2 he is 10 years old.
How the Tess Was Won - August 5, 1956 - S1-E5
Continuity mistake: Though he's leaped into someone else, we always see Sam as Sam, dressed in all the host's clothes (including glasses or sunglasses). His host is revealed only in reflections. But here, when he looks at his host-self in the mirror, the hat and clothes are all identical - except that the reflection is wearing glasses, and Sam isn't. (00:43:00)
Continuity mistake: Poirot is holding up a letter in an envelope. He turns it to show the front to Lady Mayfield. The flap of the envelope appears to be tucked in. The shot cuts to a close-up, but now the back of the envelope is facing Lady Mayfield and the flap is sealed. He then turns the envelope to show her the front. (00:44:20)
Continuity mistake: Debbie Dobson is looking through a photograph album, the pages she has open have photos of her sister Gemma. The angle changes when Gemma enters the room, just before Debbie turns the page the photos that can now be seen are of Debbie herself. (00:04:45)
Continuity mistake: When Doogie goes into his en-suite bathroom to shower, he takes off his dressing gown completely before pulling back the shower curtain to get in, at which point he gets temporarily blinded by a fan taking a photo of him with a camera. A few seconds later, he's shown putting his dressing gown back on, even though there wasn't enough time for him to have picked it back off the floor and start redressing.