Even with the correct temperature and light cycle, they still often will know what time of year it is. I have lots of customers right now whos dragons are already wanting to shut down for the winter... I think they can detect the change in air pressure as the seasons change.Your temps sound good btw.
Can she see the male? Often a female will dig to hide from anxiety, she may be uncomfortable with som'thing she can see.
i think i have a hint though. the a/c has been being used a lot this past 2 weeks with our hot spell. we usually never used it before. and we have this air uv filter thing that makes some noise. well today she kinda jumped when it kicked on. think the sound might be affecting her. if so she wont have to worry soon. since it wont be running cause we like open windows and fans. so much nicer that way. but its just been so humid/hot. i have the ac vents all shut in the basement though. so it doesnt get any colder than it already can.