At the end when Carmen is leaving the kitchen to serve her family, at first she has one plate without the lobster, then when she is leaving the kitchen, as she is turning the corner, she has the plate with a lobster. Then, coming out of the kitchen, the lobster has disappeared, then reappears again when she turns towards the tables.
When the teacher reads another note after her students leave, one of the students who just left wears a purple shirt. When she looks back in at the teacher, she is wearing a green striped shirt.