Aura Priority With Increased Aura Effectiveness vs Aura Effect on Self

When playing in a group, we noticed that my armour seemed low. Upon investigation we found the following:
I had level 21 Determination, my friend had level 20
I was under the effects of 9 Introspection notables from cluster jewels
He was wearing a jinxed Juju

Because he had more aura effectiveness, it seems his aura was getting priority on me despite mine providing me a larger buff. When he removed the Jinxed Juju, my aura took priority.