I think It's clear she did something against the rules that made JYPE terminate her contract.
I mean, KG has stated A LOT of valid reasons to terminate her contract and still has to sue JYPE to be free from It, so It's not like they let idols go just because they want to.
JPY does have a track record of letting idols terminate their contracts early.
But that is only the information we have seen in public, who knows how many others have been forced by threads to stay with the company.