I love Corona, but damn if I can't avoid fireflies to save my life. I will upload a scene after I post this. As you can see in this clip, I have fireflies all over the place. I will admit, on the first clip with all the trucks, I had some old chrome materials that were set to 999 IOR reflection. I fixed all of them and you can see in the single truck test, I still have fireflies in many other areas that have much less reflection. I'm assuming reflection is the main cause, but I'm only guessing. The full truck shot is using a simple Physical Sky with basic settings.
The full shot used 15 passes with High Quality Denoising. I also tried Noise Level limit of 5, 4 and 3 with either no change or even more fireflies. Clearly, adding more passes isn't the solution as far as I can tell. The step below the door of the truck is really bad. Upon closer inspection, I'm guessing the source of the fireflies there is the pill-shaped bumps, which are actual meshes and not Displacement.
I'm open to all suggestions.
Cinema 4D r20
MacOS 10.15.7 Catalina
Corona v7 Hotfix2