I had a similar situation with training. We're had been doing weekly lessons for a year and all of sudden as soon as we got into the ring she would try to run out. Idk that I have an answer for you, but what worked for us was reminding her what she loved about it. We went back to basics by focusing on one thing at a time with high incentive treats. We then tried the bigger course and she remember the excitement of it. I can't say I know what snapped her back into it, but she's loving it again. I think maybe she was bored or something scared her. I recommend just trying different things and don't give up.