Problem changing parent with P.View Classic !

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Hello everyone, I've been looking for a solution for several days but I'm still at the same point. In my game I have a simple trigger that when entering it changes to the parent player:

void Start()
{
myPlayer = this.gameObject;
}

private void OnTriggerStay(Collider other)
{
if (other.gameObject.tag == "Trigger")
{
target = other.gameObject;
myPlayer.transform.parent = target.transform;
}
}

private void OnTriggerExit(Collider other)
{
if (other.gameObject.tag == "Trigger")
{
myPlayer.transform.SetParent(null);
target = null;
}
}

With the actual P.View the players can change parent with that trigger without any problem.
Now, when switching to Photon View (Classic) the trigger only works 1 time for every 20 attempts. The player does not change parent but the position changes to 0, 0, 0 for the other players.

From what I interpret I guess that i have to synchronize that change of parent but I don't know how to do it exactly, if with rpc, onphotonserialized or some other method.

Has it happened to anyone who has been able to solve it?

(this trigger is just to enable the player to stay in a moving platform)

thanks for your time and help!