After reading this....

https://efupw.com/efu1-forum/topic/29/29198/potion-of-armor-mage-armor-bug/index.html

I realized my casting of mage armor has probably been bugged. I only started casting it since I picked up a second wizard level, since 5 minute duration at level one never helped much.

My character is wearing leather armor, +4 Dex, +1 Deflection, +1 Dodge. This giving me 18 without mage armor. If I did cast it, what should my appropriate AC be? I'll openly say it has been AC 23 with mage armor.

But obviously this spell isn't nearly as good as I thought it was. I'll obviously stop memorizing and using this spell, until I know the problem is corrected.