Finding: Gaining I-frames by dashing through enemy attacks will allow both your unit and their shield to take no damage, but using an Elemental Burst to gain I-frames will only make your unit took no damage, while their shield will still take damage.
Shields are more effective on characters with high defense.
How Elemental Shields having 250% Absorption Bonus to said element Work
By: Türin#8565
E/N: Submission demonstrates the above mentioned effect using the example of Diona but this also holds true for other similar character-generated shields.
Theory:
With Cryo Absorption Bonus, Diona takes 2.5 points of Cryo Damage for every 1 point of Shield HP lost.
Other shield effectiveness is not accounted for, but it stands to reason that they work the same way. We can both say that a shield has 2.5x of its current value, or the damage is reduced by 2.5x, against it's effective element.