Poison arrows bug?

[thejeff]

Should units attacked by poison arrows take poison damage even if they're not hurt by the actual arrow?

It seems to me that the arrow should have to actually penetrate to get the poison into the target.

The situation:
Androphag archers firing on a squad of Vanherse. Arrows fall among the squad. 2 troops take damage, breaking their glamor. Then on Vanheim's turn, the poison takes effect, damage 3 previously unhurt units, breaking their glamor.

I don't know if the arrows were stopped by shield, protection or mirror image.

It seems counter-intuitive that an arrow bouncing off armor or shield, or passing through a mirror image should still poison the target.