Solution: Make the damned hitbox bigger. One square meter should be sufficient...
And to give you an idea how fucked up building banners as a small group is:

Oh wow... There's at least room for two more builders, am I right? Hell no. You can't even fit one more person in this space even though most of the sign is visible and you can click on it and move toward it, but the menu won't show up. And to explain the picture, our chieftain tried to place the final branch into the build menu, but he couldn't access it due to the issues with the hitbox.
Please fix this.