What is physical reality?

If a form of interaction like a crossing over of events is defined between two different universalworldlines in two near neighbour universes after Bohms theory of many worlds in quantum physics,then local observers in the same universe can measure different values of a physical size, when oneof them is trapped in a local closed surface of the crossing over zone and the other one isn‘t in thisstate but in the state of the “normal“ universe. In this case, physical measurements are no longerclearly defined.