I have found what appear to be duplicates in the Component Hierarchy By System in the latest 2.74 release of Loinc.
Here is an example from ‘ComponentHierarchyBySystem.csv’
Line 76488: “LP432695-7.LP29693-6.LP7756-2.LP31628-8.LP31633-8.LP13943-3.LP113786-0”,“3”,“LP113786-0”,“LP427251-6”,“Arachis hypogaea recombinant (rAra h) 8 Ab.IgG4”
Line 76490: “LP432695-7.LP29693-6.LP7756-2.LP31628-8.LP31633-8.LP13943-3.LP113786-0”,“4”,“LP113786-0”,“LP427251-6”,“Arachis hypogaea recombinant (rAra h) 8 Ab.IgG4”
The only difference is the sequence value. Lines 76489 & 76491 are exactly the same, which are the children of the two above.
This is one example from many that I found, and they are also present in the hierarchy browser. Are these duplicates errors or do they convey something?