NPC attacks after death, when human sitting in car, is something broken?

Hey all, new to the forum and new to coding in Roblox. I am learning how to build a game and coding in LUA. My recent game I am working on I have NPC's that attack players. I am using the zombie NPC model built by Based_Kevin just to understand how the coding works, I have not changed much with it as it seems to work as advertised. The NPC spawns, looks for a humanoid in x amount of space, then attacks and can receive damage, then respawn in same spawn point. All this works fine when running around with my player and also seems to work fine when driving around in a car while in play mode in Roblox studio.

I noticed though that after publishing the game (private for testing) when in a vehicle and I kill the zombie, the NPC health seems to go to 0, based off the health bar and a few parts fall a part but I continue to take damage from the NPC, or at least it seems it is from the NPC because the parts are on the ground where I killed it.

I have used 3 different car types and all produce the same results in game.

Any help would be greatly appreciated.

If anyone needs to see code, please let me know which code you need, I posted the model and who its by to avoid cluttering this place up with script code.