Blue Color During Arousal

I’m just getting started with chastity, having worn it for roughly 40 days (with one release). Usually when my wife teases me, the area below gets quite red. However, on this occasion, everything turned blue. I could still sense touch, so by that standard, I was fine. We did remove the cage temporarily as a precaution. Is this typical? Should I be concerned? Is it best to take it off when this occurs? I’m using an MCN Contender which seems well-fitted except for being about 1/4” too long. It fits comfortably but isn’t tight unless teased. Just snug.