whoa. Only thing I could think of is that your rig pose fingers are different from the model pose. That differentiation confuses people, but the model pose is the pose the model came with and the pose you tend to place your joints in. The rig pose gets created when you move to deformation setup. The rig pose is the pose the rig will get built on. The ideal rig pose is a T-Pose, which there is an option to auto-create for you. My only guess is that the rig pose fingers must have gotten shifted, or maybe the whole hand. You can check by going to edit character-> edit export file, and in the UI under reference pose manager menu, choose assume rig pose and see if anything changes. If it does, you can do reset rig pose, assume model pose (to assure both are the same), and then if you want (recommended), you can hit the auto world space button (or whatever I called that thing).