Boy, what a mess. Neither team wants this rescinded.
I'm sure they want to keep the deal regardless. They weren't getting anything more valuable than that Brooklyn pick.
However, while there's already like a 75% chance that Lebron leaves next summer anyways, hamstringing that team without IT for a large portion of the season would essentially be escorting Lebron out of the door. I'm sure that's what they're worried about the most.
Then again, it could just be them trying to angle for more, specifically Tatum.