Always worked like this, same if you have the Gilden sovereign surrender to you, you get a faction-wide +25% Defense boost.

This is due to the ability to make champions cost less Gildar is located on the unit "Relias" and the Armorer trait is located on the unit "Lord Markin"

I always disliked this "feature", and hoped they would move the faction wide items to the faction traits, and keep sovereign traits being sovereign based.

Sincerely
~ Kongdej

Oh and btw, some loot items, usually letters, if they have 1 or 0 in value, they are there for the flavour.
Don't remember "Markith's Letter" in particular, the other part sounds like a bug. (Next time take a screenshot)

~ K

Oh, that one is a "flavour" item, imagine its a page of a diary or something.

~ K