Cooked Steak camping, looked Well-done initially but later looked Medium?

The user cooked ribeye steaks sous vide to 137°F and then chilled them on ice in their vacuum seal for two days before searing. Upon cutting into the steaks immediately after searing, they appeared well done, with a gray color throughout. However, about twenty to thirty minutes later, the color returned, revealing a perfectly medium-rare steak with a small gray band from the sear. This was surprising as their usual method involves sous vide, a brief ice bath, and then searing, which always results in the desired medium-rare appearance. The cooked steaks were enjoyed as sandwiches and tasted quite good despite the initial visual disappointment. The user speculates that the cold temperature might have affected the steak's color initially. They are seeking an explanation for this temporary color change, wondering why the steaks initially looked overcooked but then reverted to their expected pink hue. The core question revolves around the scientific reason for this color transformation after cooking and chilling.