Probably just a shed cycle that's taking a bit long- have you checked? (ie. lift the hide & see if she's cloudy?) And even if she isn't cloudy right now, she might have gone to "clear" by now & is getting ready to shed, so it wouldn't hurt to boost the humidity a bit.
One reason some shed cycles may take a snake longer is if (more like "when" because we all blow it sometimes, lol) you happened to feed her just as she was going into a shed, but she hadn't clouded up enough yet so you didn't notice.
Digestion & shedding both require extra hydration from a snake's body, therefore a meal can make the shed take longer- some snakes have trouble doing both at the same time so a meal interrupts the shed somewhat- this is why many snakes refuse meals when in shed, & why some snakes end up shedding in a zillion pieces that get stuck- their hydration wasn't good enough to do both functions well.