unable to inflict ailments on conqueror boss

I just did a conqueror (drox) with 70% chance to avoid elemental ailments, and I wasn't able to ignite him OR poison him (i have 100% chance to poison) after spamming my abilities on him for minutes. I am using the "Rashkalador's Patience" amulet which states "always freeze, shock, and ignite". My ailments were applying to his banners, proving that it was possible to apply ailments. I even had the new "Alchemist's Mark" on the boss and he NEVER dropped poison or burning ground, proving he never was effected by my ailments. I should have had at least 30% chance to ignite and 100% chance to poison, but I couldnt apply either ailment. I am playing hexblast poison/ignite if that helps.