After Bugs Bunny places the giant gold rock on Pierre's counter, it is gone in the next shot after Bugs walks away with the carrots.
Before Chillicothe Sam chases Bugs Bunny through every state in the union, Bugs tells Same that he has his running pants on. Near the end of the chase, Bugs no longer has the running pants or shirt on.
When Chillicothe Sam is at Fort Knox, he throws his gun away and grabs a pick, but his gun is very briefly shown in his hand with the pick, then it disappears.