When Bond is in the coffin in the cremator, we see the outside of the coffin bathed in intense flame, we then see smoke on the inside of the coffin suggesting the coffin is starting to burn.

Next, however, we see the coffin back in the room with Shady yelling at 007. Shady keeps his hand on the outside of the coffin, which should be scorchingly hot, having been in the flames only a few seconds earlier.