Shield oath does not actually give any bonus enmity at all, whatsoever.
Tested multiple times, multiple scenarios, with multiple different people.
Tested against Sword oath, with various different gear setups, tested against different races, against different mobs, everything we can possibly think of.
We have all come to the conclusion, that Shield oath does not grant *any* bonus enmity at all. In fact, you lose enmity, because of the -20% damage dealt. Therefore, in the same fight, same race, same geared paladins, using the exact same skill at the exact same time, the one who uses Sword oath will hold hate over the one who uses Shield oath, because they are doing more damage. This should not hold true, because on the skill Shield oath, it's supposed to add enmity (not double, just add). Which doesn't happen.

Sargatanas
Taggerung Juskarath
my pc specs and internet settings don't matter. This is a game bug.