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In Real Life - A writer or group of writers didn't like the last 4 issues of a 25 issue comic-book story arc, instead of a full Continuity Reboot they simply reset the story back to issue 21 and continue from there.
Alternatively - The fans didn't like so they ignore everything past issue 21 and write Fan Fiction of what they feel happened.
Justified: The time-altering super hero Chronos needs to save his girlfriend from being slaughtered after she was already mutilated and dead, so he rewinds time to a significant point and changes history and thus the outcome of the story.
Everything DID happen but it just all looks like it is happening again.