Flank Steak Sous Vide - Blood Spots?

I got a SV wand for X-Mas, so have been doing alot of that this month.

I did a flank steak today, which I cut into 3 parts, 3 bags, and did at 52 Deg C for 4 hours. I then Ice Bath'd all three pieces, and 2 went in the freezer, and one went in the fridge.

For dinner, I pulled the fridge version, and warmed up at 48 Deg C for 30 minutes while preparing Lomo Saltado fixins.

When I was slicing the steak, against the muscle grain, I ran into 2 or 3 small blood spots (bright red pockets in the meat - maybe 1" across and spread across 1" worth of slices. I took them out, but was wondering if anyone knows what they are, and what that means? I've cooked many steaks in my 30+ yeas on this earth, and had never seen that.

Second, follow on question: if I want the other 2 steaks more well done, can I pull from the freezer 90 minutes before another meal, and SV at 54 Deg C, or does "twice cooking" them introduce new problems?

Thanks in advance for your feedback!!!