When Tom & Joyce are going to bed, Joyce puts on a purple sleep mask, which is suddenly black in the next scene.
When Barnaby asks Rose to check whether she is missing any knives, she gathers them up from the table--and they are covered in flour. But when she puts them away in their rack, they are clean (and presumably she wouldn't put them away unless they were clean).
At 34:12, Tom & Joyce are in bed, and Joyce has a sleep mask that is purple satin on one side and purple velvet on the other. When she first puts it on, the velvet is on the outside; in the next shot, she is pulling it down over her eyes but the satin is on the outside; next shot, it is completely over her eyes with the velvet on the outside.
Around 1h 24m a fight scene is played back as recorded on a security camera. The camera follows the action which a fixed security camera would not do.