I don't know if something has changed recently or whether Pro Builder by Unity has a bug as they just updated there version to fix some bad bugs but I cannot import my world into VRC anymore without any Pro Builder meshes being Invisible.
Other object meshes appear fine except the pro builder meshes.
Including screenshots of what I built and how it looks in VRC.
My current private testing and showcase to some people development world still works but trying to test updates to what I have been building in local I get the second image.
Please note its a different angle where I am supposedly standing on the red highlighted foundation mesh in the first image looking to the right.