Continuity mistake: When Cleveland tells Junior to ask out Whitney, the door handles on the lockers in the background are on the left side of the locker. A few moments later, the handles are now on the right. (00:02:10)
Continuity mistake: Junior isn't able to fit through the door after returning from Choni's Cantina (the first time). Yet Junior is able to fit through the door in other episodes. (00:04:15)
Continuity mistake: When Junior starts singing and Cecilia joins in making them a duet, the shot cuts to Cleveland. After this it cuts to a wide shot where we can see Cleveland doing nothing. In the next shot, he's suddenly finished drinking from a glass. (00:11:00)
Answer: In the episode "A Rodent Like This" Rallo discovers that Cleveland Jr. is actually a secret agent who is tracking down Tim, who is actually criminal. Jr. reveals that in order to get close he had to eliminate the real Cleveland Jr. luckily Cleveland doesn't pay attention so it was easy. Whether or not this is canon or not depends on the writers.