Warrior missing Plate Armor proficiency at level 40 (Icecrown)

Realm: Icecrown
Character: Hofu

My Warrior did not receive Plate Armor proficiency at level 40.
I cannot equip any Plate items and get the error: “You do not have the required proficiency.”
Trainer shows no Plate training option, and website services don’t offer “Learn Spells.”

Running /run print(IsSpellKnown(750)) returns false, confirming missing Plate proficiency.

Please manually reset my armor proficiency flags or reapply my Warrior class spell package.

The trainer window has a filter dropdown, make sure everything is enabled.