As I’ve been doing delves and starting to max out the treasure troop ascensions (Still hate faction Crypt Keepers run), I had 6 copies of King’s Crown at mythic and didn’t realize until I mass disenchanted. The total went from 6,100 souls to 100 which at first confused me until I checked King’s Crown.
It still had 6 copies and no matter how many times mass disenchant was clicked, it never removed the 2 extra which is actually a good thing since you may have say 30 Priest’s Chalice’s over 4 and it won’t remove the 30 in case you were saving up for a new faction.