I already posted on forza support, but post it here in case someone already knew the cause and solution.
I tried creating rules of play in my event blueprint, cannot set or get value in triggering player’s variable. Also cannot refer player id and score of triggering player.
Get/set for global varibles are fine. Also it works fine if the action specify user id beforehand. Change HUD element works fine if I specify triggering player as a change target. But refering triggering players variable always return 0, referring score and player id also have same issue in my gameplay.
Kindly let me know if you have solution or something I should check first to resolve this.