My question is an extension of this question.
Does the animated shield count as being armored for the mage armor spell?
Based on mage armor's description (emphasis mine):
You touch a willing creature who isn’t wearing armor, and a protective magical force surrounds it until the spell ends. The target’s base AC becomes 13 + its Dexterity modifier. The spell ends if the target dons armor or if you dismiss the spell as an action.
I'd assume you would have to cast mage armor after activating the shield and when you retrieve the shield you lose the mage armor, effectively reducing mage armor's time durability to a single combat.
To counter the possible duplicate: I am asking about the animated shield magic item, not the 1st-level shield spell.
Best Answer
A shield is not armor
The player handbook mentions several times, distinctly, wearing armor and carrying a shield.
Some AC calculations, such as Unarmored Defense, specifically point out that you cannot carry a shield to apply its calculation, where no such stipulation exists in Mage Armor.
Here's a similar question for everyday, non-animated shields.