I have a couple of different projects with hair from different vendors (SWAM & TokoMotion. At random points in each project, the hair goes flying off the character at some point in the scene. Both projects use soft cloth physics. Turning off physics solves the problem but then the hair is lifeless. I’m not sure when this started, but don’t remember seeing it before the introduction of CC5 and iClone compatibility tweaks (I don’t own CC5). Could possibly be due to Transform keyframe changes of the character, but the hair goes in a direction that is not related to the character movement?
I would start inspecting animation clips. Some abrupt movements would certainly cause soft cloth objects (hair particularly) to fly. Also check for objects in a way of a character which have physics enabled (that might include terrains).