What are you feeding her? Is it anything diffrent? I have this issue now with my arab and my rescue colt. But this is how I have always gotten rid of the problem both horses saddled up two ridders ride away from one another come togeather again and ride away... repeat takes days. But it works.
Unfortunately my sister doesn't ride her horse, getting a saddle on Arlia is on my list of things to do as she is a lovely SB, very sweet and willing. It is a shame to have her stuck in the paddock 24/7. This is one of the reasons I really don't want to separate the two horses. I love to see them so happy together. In a perfect world it would be nice to be out and about with both horses. I am hoping that by getting Arlia going my sister will get over her nerves and get back on the horse.