Help with collision event triggering multiple times.

I am working on a game in horizon world where players throw rocks to hit NPCs (from unity asset bundles). I am encountering an issue with collision detection where a single rock hit is triggering multiple events.

Here's the setup:

• NPC has a trigger zone 
• Player throw rocks at the NPC 
• NPC should register a hit when a rock enters the trigger  and die after 2 hits
• When NPC dies, it should trigger a single  event to move a bridge to the scene

Current behavior:

• Using CodeBlockEntityTrigger to detect rock collisions
• When a rock hits the NPC'c trigger zone, the hit event fires multiple times
• After 2 hits, the bridge move event gets triggered twice

What I've tried

1. Using state flags to prevent multiple hit from firing
2. Tracking hit processing state with boolean flags
3. Using a set to track rocks that have already hit an NPC

Would really appreciate it if you could provide suggestions on how to fix this issue. Thank you