When Wally comes in from school to call Julie Foster, he leans on one corner of the chair June is sitting in as he talks to her. At one point, he is shown pushing away from and starting to leave the chair. In the next shot, he is back to leaning on the chair as if he'd never moved.
Wally supposedly is driving himself and Julie to dinner at the White Fox which is impossible because he won't get his license yet until 2 episodes later.
When Ward calls the restaurant, he obviously knows the number by heart because he never looks it up. He only dials 6 digits.
Wally is told on the phone that coffee is $0.40 at the White Fox. Wally and Julie both order the fillet of sole almondine, at $6.25 each; they both have coffee. Beaver asks Wally how much it cost, and Wally says the bill came to $12.50, and with a tip, its total was $14.37. But this doesn't account for the coffee. The bill should've been $13.30 ($0.80 for two coffees + $12.50 for dinner) plus a tip.
When Wally tells Julie Foster that he'll pick her up, he never gives her a time. He tells her later at her house, but he hasn't made the reservation yet. He actually walks to her house and Julie's brother is driving them to the restaurant.