Hello! 
The NPC health issue is known and has been mentioned several times in the trainer’s official forum threads:
- Watch Dogs 2 Cheats and Trainer for Epic Games
- Watch Dogs 2 Cheats and Trainer for Steam
- Watch Dogs 2 Cheats and Trainer for Uplay
- Watch Dogs 2 (Uplay+) Cheats and Trainer for Uplay
- Watch Dogs 2 Cheats and Trainer for Origin
The issue is that the game developers have programmed the player’s health and the NPCs health to use the same memory address. There’s nothing WeMod can do about this.
As the official thread advises, only turn the cheat on then off again when you need it (ie, you’re low on health).
Put further discussion in the official thread for the store you have the game from, please and thank you.