Random Generator generates a different number client side than server side.

If(NOT is world remote){

//your number stuff

}

there is a is world remote procedure block in the world section iirc

If NOT is world remote, not 
If is world remote

https://mcreator.net/wiki/developing-multiplayer-compatible-mods

Random chance procedures

If not marked with client or server icon next to the trigger, the procedure triggers trigger procedure on both server and client-side. This is generally not a problem as the procedure will do the same action on both sides. But some procedures use random chance when executing and these procedures can cause different outcomes when they run on both server and client-side.  Examples of such procedures are:

• Explosions
• Any procedure involving a random number procedure block
• Any other procedure that causes strange glitches in the game

For such procedures to work, you need to wrap your procedure with if statement that checks if the current world is server-side:

if NOT "Is provided world remote (client-side)"

    (your existing procedure)

You can find "Is provided world remote (client-side)" procedure block in the "World data" procedure blocks section.