The wild hunt Crystal ability blinds even when passing the save which makes them nearly impossible to defeat. My character has a high enough save to never be blinded but still gets blinded and when I check the battle log it shows I succeed my save but still get blinded

Yeah the end is painfully dumb and it only gets worse, blind fight can help also the best non-cheat way is just to constantly use the greater shout( wiz sorc lvl 8 spell, bard lvl 6) on them as the stun works on them also everyone needs freedom of movement at all times

Also, they are casting it 10+ times a round you likely rolled a 1 which is an auto-fail regardless of save total.

No and even I check and it said that I succeeded every save and it happens every time i get hit with the attack(I am a paladin with the cure blindeness mercy so I can heal myself with lay on hands). So unless I am the unluckiest person in the world you get blinded even when succeeding the save.

Yeah I'm having the same problem. Every time I enter combat in the first wave 5/6 of my characters become blinded or paralysed. I checked the log and it said DC 27, and I got a 46 (my base Fort save is in the 30s) - more than saved, which it said, but I was blinded anyway. I'm also a paladin, but don't have the blindness mercy - relying on my cleric and Jubilost who are both tanked out on remove blindness spells.

Even though I cast freedom of movement on all my characters, they still get paralysed too.

This "Against All Odds" mission really is that. It's so hard (even on story mode) and frustrating because of the permanent blinding (which means often having to return to the outside to buy more camping provisions to heal so my cleric can remove the blindness) that I'm no longer enjoying the game and thinking of just stopping - at least until a patch comes out.