When Mario, Luigi, Toad, the princess, and the leprechaun arrive at the cave to get into the castle, it's raining outside. As soon as everyone but the leprechaun enters the cave, there is no rain. Then the next shot with the cave entrance it's raining again.
When the leprechaun Murphy opens up the pot, the pasta inside is white. Then in the next shot the pasta in the pot is red. Then when Mario has it on the plate it has both red and white colors.