Question about afflictions and resistances

[paaka]

I'm a new player coming from PoE1 and doing a PotD run, and the story began when i met the Messenger in Beast of Winter (Neriscyrlas 1st phase?).

Having a tough fight with him, I tried to debuff him in some ways and realized he has Immunity to Intellect afflictions and Resistance to Resolve afflictions. But I heard that resistance to a certain affliction will only downgrade the affliction for 1 grade, e.g. from t3 to t2. So I casted Ryngrim's Enervating Terror on him. The skill hit, and the combat log did show he "resisted terrified" because of the resistance. But neither the combat log or the top-left character status showed he was Frightened, not even Shakened, and the boss continued to cast the hostile spell that he was casting (if he is frigthened he cannot be casting hostile spells?), as if nothing happened.

I was so confused and wondered if its some privilege of this awesome boss that helps him resist some kinds of debuffs, so I tried the same trick on the little mob next to him (i.e., the Luminous Revenant). That mob has Resistance to Intellect afflictions, so I tried using ringleader from Cipher on him. The spell crit and as expected the mob resisted the Dominated effect from the spell. However, it was not Charmed or Confused, at least not shown on the combat log or the character status, and the mob still fighting my party member as if its not charmed.

Am I missing something here? It seems to me nothing has been downgraded but instead the afflictions are getting blocked completely.
 

I couldn't wrap my mind around this for hours and would like to get some help from you guys, thanks in advance!