That's quite strange. Does it do that if you create a new Pipe Schedule? How about if you create a Pipe Schedule in a new Project File with a couple of random Pipes drawn? Does it appear the same way on any other computers?
I suggest that you post screen captures of the Filter tab and the Sorting & Grouping tabs of those schedules. You are showing just the end result, not the settings that might be causing that result.
I had the same issue and the solution I found is ;
In Formatting TAB
Go to Field Format...
Uncheck Use project settings
Change Rounding to 1 decimal place
Change unit Symbol to mm
You will see the Diameter, if you ask me why 1 decimal place and mm is needed to see it, I really do not know