It is possible that this could be benign and could be a comfortable position for Yusi to eat in. It is also possible that she is favoring one leg because of discomfort/pain. However, if this was the case I would expect her to be limping or showing discomfort while walking or during other parts of the day. If this is the case I would recommend having Yusi seen by a veterinarian to help assess for any bone pain or other abnormalities. If she is otherwise acting normally I would recommend continuing to monitor her.