If your object is disappearing or apparently culling itself due to its vertices going away from its root bone..... culling randomly screen or something.. just all round disappearing on camera movement - just increase the actors bounds. This took me days on end to figure out, multiple projects... and headaches. Derrrr...
Reason:
Vertices will automatically dissappear when they get moved out of the objects bounds. Sometimes animation accross a scene with a fixed root will make those rigs dissappear (typical of linear animation).
Fix
Increase the Actors bounds...