Duct or Pipe property notes show unusual or unchanging results when you size your system.
During the design process of a schematic it is a common technique to use temporary system markers during the process to check parts of the schematic. If the system sizes then the calculated result data is stored in the pipe or duct section data. If these sections become disconnected from the main system, turning on Duct or Pipe properties will display the previous calculated data, but won't include the sections in the new sizing run.
Here are three processes that should help diagnose this.