Harold's position changes when he falls into the little boat.
While being chased in the woods, the tear or patch on the chaser's shoulder changes shape and sides.
When Harold is first shown packing the money back into the pouch, he clears the table. The subsequent close shot shows the money on the table again.
When Harold first climbs aboard the ship and falls onto the deck, it is in bright sunlight. In subsequent shots, that area is in the shade of the deck-house - indicating those shots were done at a different time of day or even on the other side of the ship.
(At about 40 mins) The view shows a misprinted stereopticon card. The image intended for the right-eye is on the left and the left eye image is on the right. This produces a pseudoscopic stereo effect--visually disconcerting with near elements appearing far away yet obstructing distant elements that appear to be up front. The two stereopticon cards being held seconds later had been printed correctly.
It is easy for a careless printer to accidentally switch the views, because the left and right images usually look very similar to each other. Such an error is not noticed during card production unless the stereo pair is checked with a suitable viewer or examined by a person who can "free view" stereo pairs without using any apparatus.
The one problem with the ways Harold has devised to wash clothes and the dishes, is that he does not rinse the soap from either.
When Harold is chasing the laundry on the kite string, in the shot after the wood pile collapse, a shadow of the long, thin pole to which the string is attached is briefly visible on the ground.
The backgrounds change when the billy goat is eating the laundry.