This is beyond reliable, it's how most modern trade treaties work. ISDS has been around for a long time, it's excesses, lack of transparency, ability to decay progressive protections for consumers, workers, and the environment are well known and in no way in question.
I wish I could find a presentation I heard from CFR that really broke the issue down. Pretty much comes down to whether the benefits of trade are worth more than having clean air, water, safe workers and safe products. I'll give you one guess what the people who negotiate trade treaties think.
There is a reason these treaties are negotiated behind closed doors. If people knew what the full impact of them could be in the worst case scenario they would never get passed.
The ISDS system could be set up in a way that doesn't destroy national sovereignty but there is no movement to reform it.
It's stupid to describe this as a "leak". It's just an extension of the exiting system that no one ever expected to change.