The Simpsons has been around for decades, so it was only a matter of time before stories concerning characters and their backstories became inconsistent, often changing what was previously established without explanation. Key events in a character’s family or even what they look like can change just like that. Sometimes, this might have just been an accident on the writers’ part. Other times, this is done intentionally, possibly to reflect the passage of time or even to add to or change an established story.