I tried rendering this scene in IRay render on the last frame of the scene:
When I selected IRay render, the frame rendered is not the last frame.
It is also strange that pieces of the letters E and C that were blown up are visible, but the E and the C have not been blown up yet it looks like.
And when I render in Real Time, the Ground Plane that is invisible at frame 1,200 still shows up.
I have the same camera selected in the Render options, but it appears to be the camera position at frame 0, not frame 1,200 where I zoomed in.
I can fix the last one with a graphics program, but just though I would report a couple of possible bugs.
Maybe it is related to being a simulation, or perhaps it is related to using Blast and / or the Particle Sampler in a physics scene.
I can share this scene with you if it would help you solve it?
I will test in another project when I get a chance.