When the 3 boys are knocked off their bikes by the hosepipe the bikes disappear immediately afterwards.
The few times we see Sarah driving, when seen from this perspective of outside the windshield the gear shift lever can be seen in the park position.
After the kids throws the suitcase in the river, in the shot of them from behind looking down, a rope or something similar can be seen tethering the suitcase.
Sonny's pumpkin is obviously a foam prop. It has no "lid" carved in it for scooping out the innards.
The end of the movie takes place during Christmas season yet all the trees are fully green.
In the closing credits, Rebecca Shoemaker is listed as Seamtress, instead of Seamstress.
When Kathy is talking to Sarah in the store, (with the camera behind her) her mouth movements don't match her speech pattern.
The story takes place in New York state, but in the final scenes with Christmas decorations everywhere, it is obviously still summer.