Can collision be detected when object IsTrigger?

I have hitboxes on my character and the bullets are registering hits on it. The hitboxes are triggers and the bullet is a standard box collider. Is this the issue?

There should not be an issue. Although you will need to attach a rigidbody to either the bullet or the hitbox to work.

OnTriggerEnter // if it’s a Trigger

OnCollisionEnter // if it’s a Collider