Hey so its my second playthrough, I'm at level 50 and still no Poison resistance or immunity necklaces to disenchant.

I read somewhere that after level 20 the game replaces all Disease Resistance, Poison Resistance and Poison Immunity necklaces with 'Disease Immunity' necklaces at vendors, something about the game not being able to tell the difference. Is this true?

If so, can I still find them as rare loot? Or pickpocket them from certain NPCs that might be carrying them? (though that would take forever and would be like finding a needle in haystack). Maybe some NPCs always carry them despite the random loot generator?

I know poison attacks are rare and not really that lethal at higher levels, but I'm kind of a completionist and my Enchanter/Artificer would like to learn all possible enchantments. I found them all except fiery soul-trap on my first character.

I also give my mage followers enchanted clothing/robes with legendary boots and gauntlets and the only enchants that they can make use of for chest pieces are Light Armor, Heavy Armor, Health, Stamina, and Poison Resistance. For mages Health and Poison resistance would be the best combination then, and might prevent some level 30 followers from dying due to extra damage when taking a knee.

Phew, I know this a lot for a just a simple and relatively useless enchantment but I made my case and hope someone can give me advice.