After loosing all my lieutenants with + fire damage perk in the last patch, i decided to farm up some new ones. The purple lieutenant i recruited was fine, his buff was still fire damage and so i hired him. But the legendary one that i recruited instantly became fire arrow damage in the menu.
I saw the fire damage icon when scouting with Ikaros, recruited them, check the menu and it's now changed to fire arrow.
Wierd...