See my post above and clear any old trainer data.
the weight management things is quite manageable without the trainer, its a lot easier just to force yourself to remember to make sure you eat, every 15-20 minutes just pop 1 or 2 cans of food since game time is accelerated and i havent had a single issue with being underweight
i can confirm its the Fall damage cheat giving mobs and NPC invincibility,
I'm not using the Fall damage option and I'm getting NPCs that are invincible. Unable to complete some missions because of this.