Hi,

I tested Zodiac nodes and gear prefixes with "Damage increase against Debuffed enemies" and it turns out only Debuffs that classify as Status Effect Debuffs (chill, shock, wound, blind) count towards damage increase

There are multiple other options that include "Debuff" wording in their description, but none of them count towards bonus damage, unless these specically do correct status effect.

For example

1. Curses from Avatars (Hamal: Curse of Decay, Alyssa Curse of Weakness, Boreal Curse of Power, Casthor/Aquila Curse of Speed, Acuben Curse of Storm (unless specifically target being shocked), Leo Curse of Pain, Vesper Curse of Withering, Capri Curse of Heat, Miserati Curse of Blizzard (unless specifically target being chilled). All of these curses have deliberate description "Curses are classified as Debuff skills".
2. some Totems (Weaken Element Totem, Tremor Totem, Mist Totem, Spell protection Totem) have specifically written description "Applies as Debuff effect" on it's card.

All these have clearly written Debuff tag (even with capital D) written on them, yet none of them count towards "Damage increase against Debuffed".

So, either

1. it's a bug and these are correcly Debuff skills and should be counted towards Debuffed bonuses
2. or this behavior is correct, but then corresponding description must be changed.

There is no information or limited on either Zodiac or gear prefixes, that only those specific status effects count towards being Debuffed or that these Debuffs have to be status effects.