EXFO iOLM - Manual (Page 136)

Managing Results
130 iOLM
Managing Elements and Analyzing Links (Optional, iOLM EXpert and Loopback Modes)
When you add a new element to an element or group of elements, the
Loss and Reflectance values are set to “---” and the Pass/Fail threshold is
not applied to the newly added element. Accordingly the status for the new
element is reflected as unknown. The global pass/fail status can be
affected after adding an element on an existing element. The added
elements are taken into account to determine the pass/fail status of group.