Hey, had similar issue, when corona 12 either not rendering or crashed in IR render. In my case - in one of the scenes, I had corona scatter with edge trimming enabled on the chaos scatter rollout. And one of the instanced object that was used for scattering had edge trimming map in opacity slot. Even tho it was disabled in material, it still would crash. Once I've removed the map - it started to render without the problem.
In 2nd scene I as well had chaos scatters, tho I did not had time to check if any of the scatter objects had trimming map, removing chaos scatter for good helped.
UPDATE:
In 3rd scene, I did not had any scattering at all. The scene crashed as soon as I've opened material editor or started IR render