I might be wrong but...
Think logically, you weren't changing the right things:
If this was the place your health was removed, then every single time when you got hit/died, all of the enemies would've got the same amount of damage aswell, as you said it made your enemies invincible. According to that there must be something more to it, I suppose.
As for the position values, it might be a security system, so you could 'teleport' and it checks whether you've gone too far too fast and then takes you back. You will probably have to trace down the check, which can be hard