In a fast-paced multiplayer game I'm working on, there is an issue with the interpolation algorithm. You can see it clearly in the image below.

Cyan: Local position when a packet is received

Red: Position received from packet (goal)

Blue: Line from local position to goal when packet is received

Black: Local position every frame

As you can see, the local position seems to oscillate around the goals instead of moving between them smoothly. Here is the code:

    // local transform position when the last packet arrived. Will lerp from here to the goal
    private Vector3 positionAtLastPacket;

    // location received from last packet
    private Vector3 goal;

    // time since the last packet arrived
    private float currentTime;

    // estimated time to reach goal (also the expected time of the next packet)
    private float timeToReachGoal;

    private void PacketReceived(Vector3 position, float timeBetweenPackets)
    {
        positionAtLastPacket = transform.position;

        goal = position;

        timeToReachGoal = timeBetweenPackets;
        currentTime = 0;

        Debug.DrawRay(transform.position, Vector3.up, Color.cyan, 5); // current local position
        Debug.DrawLine(transform.position, goal, Color.blue, 5); // path to goal
        Debug.DrawRay(goal, Vector3.up, Color.red, 5); // received goal position
    }

    private void FrameUpdate()
    {
        currentTime += Time.deltaTime;

        float delta = currentTime/timeToReachGoal;
        transform.position = FreeLerp(positionAtLastPacket, goal, currentTime / timeToReachGoal);

        // current local position
        Debug.DrawRay(transform.position, Vector3.up * 0.5f, Color.black, 5);
    }

    /// <summary>
    /// Lerp without being locked to 0-1
    /// </summary>
    Vector3 FreeLerp(Vector3 from, Vector3 to, float t)
    {
        return from + (to - from) * t;
    }

Any idea about what's going on?