Heroics randomly not giving Northrend Adventuring Supplies at completion

Something like 60% of the time I complete heroics I am receiving a box, but the rest of the time I am not. Before every dungeon I make sure to check that my role is correct. I only tank or heal. I don’t understand what is going on.

are your bags full? because it doesnt create it when the bags are full.

which i think should be considered a bug. they should mail us the boxes.

I’ve had it not give me a bag if I’m stunned when the boss dies.

most likely a user error. bags full.