When Ward is fixing the refrigerator light there is no hood over the range and no shadow on the refrigerator. Later, in the same scene there is a decorative hood over the range and it casts a shadow on the refrigerator.
Ward gives The Beaver a book he says is about the War of 1812. Later, while discussing it, Beaver shows his Dad a full-page illustration. When it is shown onscreen, the facing page reveals that the book Beaver is holding is an encyclopedia. Entries visible on the facing (text) page include "BOYLE'S LAW", and "BOYNTON, Edward Carlisle". Apparently the illustration was pasted or taped into the encyclopedia for the closeup.