Omen of Amelioration used when dying in 0% loss boss fights

To reproduce, just go into a boss fight with an omen of amelioration in your inventory. The one I lost it in was the Maven.

Expected: 0% xp loss boss fights do not use an omen of amelioration if you die during that boss fight
Observed: 0% xp loss boss fights use the omen of amelioration if you die

If you're busy mapping / leveling in high levels (97 for me) it's easy to forget if you have an omen in your inventory when you decide to do a change of pace and do a boss fight.