What Is This Imperfection? Carbon/Resin Platinum Ring

Hi! We bought my husband’s wedding ring in Sept 2021, and we noticed this imperfection the day after we picked up the ring. Due to life getting in the way, we never went back to the jeweler to find out what it was and to see if we could get it fixed.

This is a very heavy platinum ring, and the black part is what my husband says is “carbon with resin something” lol… 😂

Anyone know why this imperfection or defect is here? It seems to be inside the carbon/resin… it’s not a scratch. Any idea on the cost to fix it if we ever wanted to? Two photos included.