Design Size of Major Pipeline and Size of P1 Pipe Run not linked?

I am working with Bentley(R) OpenPlant PowerPID V8i (SELECTseries 5) - Version 08.11.10.202

When inserting a Major Pipeline for the 1st time, the Design Size on the Major Pipeline and the Size on the P1 Pipe Run are in sync, when you change the Design Size the Size updates. (But not the other way around)

After you have inserted the pipeline into the drawing and change the Major Pipeline Design Size, the P1 Pipe Run Size does then NOT update. I need these 2 to be linked, because in actual fact P1 is the Major Pipeline. If I insert another P2 Pipe Run that Run can then have a different size, but P1 and the Major Pipeline will always have the same size.

How can I have these 2 linked that they update when the other one is changed?

Any help would be appreciated.