The catalog function Instance.isModified(<concept>) returns true when the concept has been modified in current RTC cycle.
Issue/Introduction
How to use Instance.isModified()
Environment
All Operating Systems
Resolution
The concept is marked as modified only after the Rule that modified the concept is processed. That's the reason catalog function Instance.isModified(<concept>) still returns false when called inside the Rule where concept was modified.
Note: The parent concept is marked as modified when we modify one of it's child concepts.