Gray band troubleshooting

Kept wondering why I'm getting gray bands on my steaks even after I follow all the common tips, dry steak hot pan lots of oil pat dry etc.

Decided to check my unseared cold steak and look at that, a gray band. Of course no matter how good I sear it, it won't get better only worse.

This is a striploin steak cooked at 131f for 2.5 hours from frozen, then refrigerated, sliced cold straight from the fridge.

I check my anova sous vide from time to time with thermometer so the temperature seems to be on point. Could the reason be that the steak was frozen and it somehow messes with the surface?