Drop relics from bosses (The Witcher 3: Wild Hunt)

It turns out a strange garbage - no matter what the boss kills, objects fall, although relics, but 5-10 lvl less than mine, which excludes their use. weapons usually fall, but pants fell out 1 time, does anyone know what to do in order to get an item at the same level, the smartness of bosses + 10-15 above themselves does not solve the problem.