Translate not working properly

Are you sure? Try printing the distance between the start and end points to console.

 Vector3 start = transform.position;
 transform.eulerAngles = new Vector3(-30f, 0f, 0f); //O$$anonymous$$
 transform.Translate(Vector3.forward * 3f); //here is the problem
 Debug.Log(Vector3.Distance(start , transform.position));

Are you sure there's nothing else influencing your object? This works fine:

 using UnityEngine;
 
 public class $$anonymous$$oveSome : $$anonymous$$onoBehaviour {
 
     void Awake () {
         Vector3 previous = this.transform.position;
 
         transform.eulerAngles = new Vector3(-30f, 0f, 0f); 
         transform.Translate(Vector3.forward * 3f); 
 
         Debug.LogFormat ("I moved {0} units", (this.transform.position - previous).magnitude);
     }
 }

I think you're reading the object's position as Z = 2.598, but the Y = 1.5. That is a total of 3 units.

heyy godoy! can i know how u solved that issue? because i m facing with the same issue too