There is a toggle zombie option and the trainer notes telling that you have to deactivate infinite health and first choose your side on the trainer (plants or zombies). If you had one side activated and then switching to another, the first still may still have very high health.
I've tested both sides with differents characters in different missions and never experienced the health cheat to work for the enemy side unless I made the mistake by switching sides while infinite health was active.
I tested around more as well and it only bothers with that map. i think its a map problem and not a trainer problem since the map has more problems so nevermind what i said and thanks for the trainer