I have imported an Alembic file as a geometry cache.
When I place the object into the game the animation is running correctly but the lighting is completely wrong. It look as though:
a) The lighting is ignoring all other games objects (eg if you place the animation inside a dark room with a bright light outside it appears to ignore the fact that there are walls in the way that should be blocking the light)
b) The lighting appears to be baked into the object. As the animation steps through the frames the lighting does not change at all.