i’m certainly no rabbit expert, but my guess is that it could maaaaybe be fear..?
what possible predators for rabbits live in your area? does the rabbit eat greens and/or pellets while she’s out there or does she avoid them too? where did you get your rabbit?
rabbits are prey animals so i’m thinking that maybe she could just be in fear of something she hears, smells, or sees. if she’s not eating anything else while in her hutch, that could be more proof of this, as well as if she’s lived completely indoors all of her life before you got her. maybe she’s not used to being outside.
i’ll say it again, though – i honestly have no clue! those are just my thoughts on what it could be. i’m sure there are other people on this forum who’ve had similar experiences to yours and will have better explanations. my rabbit Sienna has lived in my room with me ever since i got her, so i wouldn’t really know.
edit: i finished submitting and noticed other people responded. whoops. i guess you’ll have more ideas.