Omen of Amelioration not triggered

I encountered a server disconnection, just after starting a delve run. After client restart and login, I noticed that i lost 10% XP even though I had an Omen of Amelioration in the characters inventory. Must have died due to burning ground or something like that.

Just happend to my char on 94% to Lvl 100. Sorry, but it kinda sucks :(