War Banner - no glory gain

As the title says, I used War Banner for two or three instances and never gained glory. I'm attacking with Permafrost Bolts, Fragmentation Rounds, High Velocity Rounds and Armour Piercing Rounds. Tried without supports and with Prolonged Duration I.

Is it bugged or am I missing something?

I too am Mercenary and cannot gain any glory stacks.

nvm im dumb

same issue

I couldn't figure it out either...
but got an answer from elsewhere :

it's not an icon on the top left of the screen like I thought it would be,
but actually a slowly filling up progress square around the skill icon.