This is just a last minute cash grab by the estate to squeeze as much money as possible from the studios by threatening them to lose potentially hundreds of millions of dollars at the box office which could affect hundreds of jobs and the future of this new DCU franchise.

Instead of filing this when the copyright agreement ended or when production was first announced years ago, they waited until just months before the release and right before the marketing campaign begins so that the studio will be more likely to give them a quick payout instead of this actually going in front of a judge.