Master buffer one triggers can only be fired in the instance by the current master. If anyone else initiates the trigger, nothing happens for people in the instance. These triggers are still buffered even though master did not initiate it and will execute for late joiners.
Example test world: wrld_dd6e4119-0198-497e-b913-b6054189f84a
there are 256 cubes, each with a MasterBufferOne OnInteract SetGameObjectActive to a cube above it. Have two people join the room. Have non master click a box and rejoin the world. See that the clicked box is now active for the person that just joined.