https://forum-en.gw2archive.eu/forum/professions/warrior/Comprehensive-list-of-Warrior-bugs-2
The third post down says this: “Battle Standard: Tooltip says it revives allies, but it only revives downed allies, not defeated ones. Defeated NPCs are revived.”
I’m not sure if it’s supposed to revive defeated allies or not. Seems like if it did it’d be a little OP for PVP.