I did some testing during a game last night.
I had Guardian wind, and 3 Air shards, which should have given my troops a 30 Dodge versus Ranged. Against the average militia member with a bow, whose accuracy was 60, that should have given them a 30% chance to hit.
Across four city fights, not one single archer missed one shot after Guardian wind was cast. These were large, well developed cities with roughly 4-6 units of archers per city. These fights took a good handful of turns. No bonus was listed in the unit sheet on any of the units, though the enchantment was listed on each of them.
The next four fights against (admittedly slightly smaller cities), I cast Obscuring Fog and not Guardian Wind, which only should have netted 12 dodge total (6 and then 6 more versus ranged according to the XML). Those fights the enemy missed occasionally, but not as much as a nearly 25% reduction in accuracy would have suggested. Additionally, the bonus listed in the unit tooltip was restricted to the global dodge bonus, and not the ranged.
It does not appear that any bonuses against ranged attacks are working, and in fact Guardian Wind seems to be harmful to cast (60% accuracy becoming 100% hits on units with no dodge trait).