My horse a mare has the same issues in the field with a filly we acquired. When I trailer her away the issues seem to disappear but when riding around our acreage with the filly she is excited especially if things are happening around the filly. She was also doing some small bucking.
On my last ride on the property with one of our other horses she seemed more relaxed. Maybe it just takes time. Try working her and gradually increasing the distance over time or trailer her away for a ride.