I'm guessing you're going to say this isn't a bug, but why can't you convert more than 1 of an iconic agent? I have 3 of the equistrielle horse and I can only put 1 in one of the slots for the uncommon conversion, I want to put 2 of them as I can never use that 2nd one anyways, and that's the whole point of the conversion, to convert agents you won't use to stronger ones. It would be nice as well if you could put an iconic one in a conversion if you have multiples and one is questing. I get that technically conversions are "quests", but they shouldn't be, they are upgrades that are instant, they shouldn't have the same limitations as the regular quests.
Duplicates are broken in general, iconics just get it worst. It can't seem to sort them out, from commons on up. It's especially apparent if an agent you have duplicates of gets incapacitated.
Iconic agents cannot have more than one copy active at a time. This means you cannot put more than one on a conversion quest (or any other) at a time.