Multiplayer - synchronization of a continuous Resource Bar

Hi guys!
There is something I don’t understand here and any insight would be very much appreciated!
I’m trying to use a continuous resource bar in my main project but I had difficulties to do so : although I added the Multiplayer Behaviour on it, it didn’t synchronize at all…
So, I opened a blank project to better test things out and in this blank/mock project, my continuous resource bar DOES update. The scene looks like that :

  • Red Square = P1. // Blue Square = P2.
    When P1 touches the big black square, it adds 1 to the Resource bar every frame.
    When P2 touches the big black square, it substracts 1.
    This does work and synchronize very well.
    BUT I’d like to understand why when I press a key to reset the value of the resource bar and set it to 0, it doesn’t synchronize and both players have different resource bar values.
    I’ve tried several things but can’t manage to get it right!
    Here is the code I use :

Thanks!