The Grape's car is shown to have hit a tree stump down a hillside. Later, it is shown to be functioning without damage. It is definitely unlikely that a car that just hit a tree stump could still be functional without at least some damage to the grill or hood.
When Junior's dad is talking to the grapes, his tie is glitching due to a rendering error.
After the Grapes of Wrath's truck crashes into a stump and Tom and Rosie argue after they flew out, Rosie was seen levitating on top of the ground, not touching it.
As the Grapes of Wrath's truck is driving, the wheels are sometimes seen sunk into the ground, not directly touching above the ground.
Junior states that he's in the Liliopsida genus. Liliopsida is not a genus, but a class.