Continuity mistake: After the party, a girl with a maroon shirt and grey skirt runs out of the house twice.
Factual error: The amount of time it takes PAT to produce things in the kitchen is completely unrealistic. The items show up way before they could realistically arrive on the platform once they are requested.
Suggested correction: I've thought this too as this is certainly impossible of modern technology we have today. However, the theme of the house is it's a house of the future. It's capabilities make it amazing because nobody can understand how it's done. I think it's reasonable to assume that this house has technological advances that will only be available some time in the future; and I wouldn't be shocked if there's a point in the future where technology is so advanced that food can be produced in an instant.
Other mistake: It's reasonable to assume that the house can hide small things like posters and even shelves when projecting images on the walls. When Ben's two friends arrive for the party, one of the walls shows an image and the couch disappears, and that's just way too big of an object to simply phase away, given what we see that the house can do.