Shedding w/o going into blue?

[MnGuy]

I have two garters. One is almost a year old and the other one is about half a year old. They live in separate tanks.

My big snake is in blue right now and I can clearly see that. She came out of her humid hide for a moment yesterday.

My small snake has not been in her humid hide. She was out in her regular hide yesterday and I took her out to handle her and clean her tank. She looked completely normal.

But I woke up this morning and found a fresh shed in the small snake's tank -- the snake that did not appear to be in blue at all. I was shocked, because I had seen no signs of her in blue. I've seen her in blue before past sheds, or, she would disappear into her humid hide for days. She did neither this time.

Is that common? How/why would a snake shed without going into blue?