I understand her conditions have been constant, but you never, what didn't throw them off yesterday, may throw them off tomorrow. Your temp gradient between warm and cool is a bit narrow by most standards. Bumping the warm side up to around 90 degrees could help. If a snake is too cool to accomplish proper digestion, nature would most likely take over and keep her from eating as a safety measure. Just a thought.

How do you measure your temps? Ambient air temp or spot temp on the floor of the tank where she's at? Do you use an analog gauge or a digital thermometer?