A good example of what he says are the Zandalar token reward items. Example (from my Hunter's POV):
BELOW: WHAT SHOULD HAVE BEEN DISPLAYED IN GAME:
==============================================
Zandalar Predator's Belt (EPIC)
Binds when picked up
Waist Mail
221 Armor
+12 Intellect
+20 Agility
+12 Stamina
+9 Spirit
Durability 50 / 50
Classes: Hunter
Equip: Improves your chance to hit by 1%.
http://db.vanillagaming.org/?item=19832BELOW: STATS OF THE ITEM IN NOSTALRIUS SERVER
Zandalar Predator's Belt (BLUE)
Binds when picked up
Waist Mail
224 Armor
+12 Intellect
+18 Agility
+12 Stamina
+7 Spirit
Durability 50 / 50
Classes: Hunter
Equip: Increases damage by arcane spells and effects by up to 11.
======================================================================
BELOW: WHAT SHOULD HAVE BEEN DISPLAYED IN GAME:
==============================================
Zandalar Predator's Mantle
Binds when picked up
Shoulder Mail
326 Armor
+22 Agility
+15 Stamina
+11 Intellect
Durability 85 / 85
Classes: Hunter
Equip: Restores 4 mana per 5 sec.
BELOW: STATS OF THE ITEM IN NOSTALRIUS SERVER
Zandalar Predator's Mantle
Binds when picked up
Shoulder Mail
326 Armor
+22 Agility
+15 Stamina
+11 Intellect
Durability 85 / 85
Classes: Hunter
Equip: Restores 4 mana per 5 sec.
Equip: Increases damage by arcane spells and effects by up to 16.
http://db.vanillagaming.org/?item=19831====================================================================
The version of the items which is in force and used by Nostalrius is the bottom one and NOT the top one as displayed in the database.
I was able to verify this by using the Theorycraft addon, i.e. the belt actually increases arcane spell damage and doesn't grant you 1% to hit.