Default [Q] Internal SD half size after 4.3 root

Hey all - Noob here, but could someone let me know if they've had this prob??

This week I went stock using Kies. My internal card showed 32GB. Then I rooted using the latest method that allowed me to remove Knox. All worked fine. BUT the internal card only showed 12 GB when I was done. Is this the root method that causes this??