Anything duplicates with war spoils. It even dropped vanilla commanders before they made some changes. I have seen 2, I know what I have seen.
As for your sigh, come on, no need for such a conversation.
Cause in my whole time playing CoH2 i've never seen double Guard Motor or Jaeger Armor for example (the vanilla commander which might be duplicated are the ones which were acquired by leveling up on prestige) nor Conscript/Grenadier +3% accuracy. That would be broken and i'm sure any of the competitive top50 players would be stacking those if possible.
I guess if i want the answer i'll have to dig in the files.