Audio problem: At Thomas J's memorial service, Vada goes up to the coffin crying. Just after she says something about his glasses being missing, her father comes up to comfort her. Watch his mouth - he is heard talking but his lips aren't moving at first (they are in the next shot).
Audio problem: When Vada and Thomas J are running away from the bees, Thomas J yells, "Run faster, they're after us", but his lips aren't moving. Neither does Vada's, when she replies, "I am running faster."
Chosen answer: Most likely because there was no reason for a scene of them together to tell the story. It is assumed that because Thomas and Vada are friends, that Harry has interacted with Thomas many times before. There could have been scenes filmed with the two actors together that was later cut from the final film. This often happens to quicken the film's pace, shorten the running time, etc.
raywest ★